Boring 390's

[frnkeore]

I'm a old mechanic, hot rodder/street racer and later a formula car, road racer.

Back in the 60's, it was common practice, to bore all engines 1/8", with the exception of the SBF. I know that Ford started using it's thin wall casting technique on the FE at some point. What was the year that that started? 

I've started looking for a 390 block for my base and would like to find one of the earlier ones as, I would like to do a 4.125 or 4.13 bore but, I'm not going to use Ford rods so, 428 pistons won't be a option.

If I can't find a early block, how large can you bore the thin wall 390?

 

[plovett]

Bore as little as possible.  Some 390's can go 0.060", but that is not a good idea in general.  I had one bored .080" over and it split a cylinder wall.  An 1/8" or 0.125" overbore is not doable on a 390.

JMO,

paulie

[Sand hauler]

Usually .040, but always do a Sonic check for core shift first to make sure. Unless you go with an aftermarket block BBM, Pond, Shelby, ECT . I believe that BBM also has 428 blocks also, just have to email them about it. The aftermarket block will go much larger.

[Yellow Truck]

I'm a old mechanic, hot rodder/street racer and later a formula car, road racer.

Back in the 60's, it was common practice, to bore all engines 1/8", with the exception of the SBF. I know that Ford started using it's thin wall casting technique on the FE at some point. What was the year that that started? 

I've started looking for a 390 block for my base and would like to find one of the earlier ones as, I would like to do a 4.125 or 4.13 bore but, I'm not going to use Ford rods so, 428 pistons won't be a option.

If I can't find a early block, how large can you bore the thin wall 390?

Pretty sure they were thin wall from the start. The 406, 427 and 428 blocks were specially (meaning more carefully) cast to avoid movement of the casting within the block. The issue with the 390 blocks was that they were done as cheaply as possible, which meant tolerating some casting movement, and having a slightly thin side in a production engine was not going to be a problem at a 4.05 inch bore. The 406 and 428s were 4.13 and the 427 was 4.2328 bores. You can't get there with most 390s, and you can't really over bore a 427 since the spacing is only 4.63 inches.

[frnkeore]

Paul,
With all due respect, I would have to have references for saying that early FE's were thin wall castings and that the 4.63 bore spacing, is the reason. The first report of thin wall castings, for Ford was for the '60 Ford Falcon (144/170) and in '62 for the SBF.

BTW, the 4.63 bore spacing, came from the 317/368 Linc/Merc, Y block engine (3.8- 4.0 bore). Another under appreciated short lived Ford engine. But won the PanAm race for Ford.

The 221 through 302 SBF, has a 4.38 bore spacing and they had 4" bores by '64. Even the '63, 427 had more room, between bores than the 289. I never heard of thin wall FE castings until much later than '63. I was born a Ford lover and racer (my dad worked for a Authorized Ford Rebuilder, shortly after I was born, in '44). I read everything regarding Ford, from the time I was at least 15 ('59), on. If it was in Hot Rod Magazine (and it would have been) I would have read it or in the Ford "Shop Tips" that was available from Ford Dealers when I was a mechanic.

Here is a small part of a article by Ak Miller and Lee Kelly, from 1971, where he suggested boring the 390 to 4.13 to clear 427 valves and calling it common. Not many people knew Fords better than Ak Miller.

[blykins]

I wouldn't recommend doing anything like they did it in the 60's....LOL

If you bored ANY Ford block an 1/8", you'd end up with a mess in the cylinders.   A 390 starts as a 4.050" bore, taking another .125" out would put you at 4.175".  Extremely thin.  A 428 starts as a 4.130" bore.  Taking another .125" out would get you to 4.255".  Thin.  A 427 starts at 4.230".  Taking .125" out would make a mess. 

Even on a 429/460, which starts at a 4.360" bore, taking .125" out would put you at 4.485", which isn't advisable.  Typically, .080" over is about all she wrote on those. 

So what do you think you'd gain by going to a 428 bore with a 390?  You gain 15 cubic inches and thinner cylinders.  Yes, you may gain a little help from an unshrouded intake valve, but I'd rather have a more stable and solid cylinder wall.   

With the new cylinder head and camshaft technology that we have today, there's 100's of ways to make big horsepower without compromising a good block. 

When I do a new build, I will generally try to open the cylinders up the least amount that I can.  With full custom pistons available, if I can get a round/straight bore at .005" over, then that's the way I go. 

[My427stang]

Agree with Brent 100%, periodically I find a decent 390, but I also had 2 that were real thin at .030.  I can't imagine a .125 cut, unless you find a real good block.

Make the bore straight, spend the dough on heads, intake and headers, if you want more displacement, add stroke

[falcongeorge]

there are a few 390 blocks around that will go +.080 and still be thick enough, but they are not common, and to go out and hunt one down is probably an exercise in masochism, if not futility.you willneed to sonic test any potential candidates, and if they are pitted on the water jacket side, you can still be in trouble. Brent alluded to the primary reason to do this, unshrouding a 2.19 intake valve. Its always about the cylinder heads.
 I wouldn't even consider trying to take any OEM FE block to +.125.

[blykins]

….and if they are pitted on the water jacket side....

That's the heavy hitter right there.  You can't sonic every single portion of a cylinder. 

[falcongeorge]

….and if they are pitted on the water jacket side....

That's the heavy hitter right there.  You can't sonic every single portion of a cylinder.

Its an issue. Depends somewhat on how thick the sonic test shows, and which way the core is shifted too.

[Yellow Truck]

Frank, I don't claim any special information. Having said that, I have never read anywhere that early FEs were not thin wall. I have read that Ford's reason for the FE architecture was the thin wall casting to create a lighter block. My mention of 4.63 spacing is that it tends to limit production bore sizes, and later over bores, particularly when combined with the casting techniques and metallurgy of the period. The Lincoln Y-block 368 was a 4 inch bore, I imagine limited to some degree by the spacing.

BTW, the comment in the article about 428 bore sizes on 390 blocks does NOT describe what tests he did to do it, you can almost guarantee a lot of blocks didn't pass the test, and that some that did still failed.

Sadly, there isn't a treasure trove of special FEs out there we can use.

[blykins]

I went through 2 once.  They sonic tested ok, but it was the pitting that got me.  Scrapped both.

[FERoadster]

I've got a C5 FE block that has been cross bolted but it's already bored +060 and needs a cleanup.
The attached sonic check shows me that I won't take it to +080 due to #5 and #8.
But I plan on using custom sized pistons from either Brent or Barry to make this a nice street engine with either a 4.25 or 3.98 crank.
I've got a couple of EDC engines that I may have sonic checked to see if they are somewhat thicker and a number of 105 blocks.

Richard >>> FERoadster

[falcongeorge]

I've got a C5 FE block that has been cross bolted but it's already bored +060 and needs a cleanup.
The attached sonic check shows me that I won't take it to +080 due to #5 and #8.
But I plan on using custom sized pistons from either Brent or Barry to make this a nice street engine with either a 4.25 or 3.98 crank.
I've got a couple of EDC engines that I may have sonic checked to see if they are somewhat thicker and a number of 105 blocks.

Richard >>> FERoadster

#5 is thick on the major thrust side, depending in the state of the water jackets, if that were mine, I would SERIOUSLY consider doing a fill to the bottom of the water pump holes, banging a sleeve in #8 and going to 4.13, but that's just me. That's a good block, almost all cylinders are shifted toward the major thrust side. You would still be well over 1/8 on the major thrust side in every hole except #8, one sleeve and its an excellent candidate.

[falcongeorge]

Whats ironic about all this is the OP is looking for an "early one". Hes looking in the wrong place

[frnkeore]

Frank, I don't claim any special information. Having said that, I have never read anywhere that early FEs were not thin wall. I have read that Ford's reason for the FE architecture was the thin wall casting to create a lighter block. My mention of 4.63 spacing is that it tends to limit production bore sizes, and later over bores, particularly when combined with the casting techniques and metallurgy of the period. The Lincoln Y-block 368 was a 4 inch bore, I imagine limited to some degree by the spacing.

BTW, the comment in the article about 428 bore sizes on 390 blocks does NOT describe what tests he did to do it, you can almost guarantee a lot of blocks didn't pass the test, and that some that did still failed.

Sadly, there isn't a treasure trove of special FEs out there we can use.

What you do not realize, is that Fords "Thin Wall" technology  did not occur until the release of the 1960 Falcon 144/170 engine. It was advertised a lot when it was released. It was again advertised when the 221/260 came out in '62, never before that. I would be interested in your citation of the FE being designed as a thin wall engine.

The FE engine was not, what you would call a light weight engine. The industrial engines, weighed in at 711-720 lb (I have the specs for those) based on that and my recollection, the car engine was in the 670-680 lb class, with cast iron intake and water pump. Has anyone weighed their engines with aluminum intake and water pump?

The 317-368 Linc/Merc engine was another one commonly bored 1/8". All engines, designed before '60, where commonly bore 1/8", including the SBC 283's. Although, I don't remember 327 and 350's being bored 1/8" but .060, for sure.  For those that say a Ford can not be bored even  a 1/8th, I have to refer you to the flathead engine, that was commonly bored 3/16 (I had one) and could be bored 1/4" on some blocks.

With the "thin wall" engines, Ford was able to decrease the distance between bores to .38 and still use .040 over, SBC to .40 with .060 over and Siamesed cylinders to .255-.275  and still allow a overbore. Take that technology to the FE and you get 4.25 - 4.375. Only the limited production, 427 had anything like that. Another reason I don't believe the early engines were "thin Wall".

Regarding block testing, I don't think anyone did that, prior to '80 and as a mechanic, between '62 and '70, I never heard of a cracked FE (hell, they weren't even called FE's before at least '75). The only racked blocks I ever saw was a std bore 350 SBC, cracked in the bore and a 312 cracked in the main bearing web. You also have to remember that the FE stands for Ford Edsel and that Edsel engine started life, in '58 at a 4.05 bore with .060 over pistons available.

Just a guess on my part but, the 352 casting numbers might mean that they used the original 352 sand cores on those blocks.

I'm not trying to say, the criteria that you are using is wrong not at all! What I started out looking for was the approx date that the FE was changed to a "thin wall" type engine and I would be interested in knowing the weight difference from that, if so.

I do not have a citation to back up, that they where changed, it's just something I read, at some time. From the response, that I'm getting, it sound like the if there was a change it may have occurred early (like '65/'68) and then a change that involved truck and 428 type blocks?

[Heo]

What i know for sure is i have a 64 block  cast in 63 that
is .060 over and sonics thin in one spot (.105) not much
thicker in other spots. It have the knobs for crossbolts but
not machined as such

[frnkeore]

I've already dated myself but, I have a question:

Do any of you remember Ak Miller? He was a Ford employed performance expert. He knew all things Ford and had access to the Ford engineering staff. He did special projects for Ford, modifying, almost all Ford engines.

Here is a additional part part of his '71 article, where he reinforces boring 390's, .080 over, to 4.13.

Again, I'm not trying to tell anyone what to do, I'm just looking for info and sharing mine.

Sorry, the pic isn't that good but, readable.

[falcongeorge]

Do any of you remember Ak Miller?

Yes, very well, and more than just an article in Hot Rod. but we are really beating a dead horse here.

[mike7570]

390 C-4 Block I sold a while back. Another .046 over? not too likely.

[blykins]

I've already dated myself but, I have a question:

Do any of you remember Ak Miller? He was a Ford employed performance expert. He knew all things Ford and had access to the Ford engineering staff. He did special projects for Ford, modifying, almost all Ford engines.

Here is a additional part part of his '71 article, where he reinforces boring 390's, .080 over, to 4.13.

Again, I'm not trying to tell anyone what to do, I'm just looking for info and sharing mine.

Sorry, the pic isn't that good but, readable.

I hate to sound crass, but I've heard of the name and he is wrong. 

Yes, we are beating a dead horse, but I would not reinforce to anyone to waste a good 390 block by trying to take it to a 428 bore.  You're much better off with having thick/stable cylinder walls and make up the cubic inches with a different crankshaft, or just flat out make more horsepower with better parts than we had 50 years ago. 

Again, what do you expect to gain from going to the large bore?  A 2.190/2.200" intake valve will work perfectly well on a 4.080" bore size and make big horsepower to boot. 

[FERoadster]

Interesting that Mike7570's C4 block has the 2 bolt engine mount pattern and my C5 has the 4 bolt hole pattern.
Was C4 to C5 the changeover?
Richard

[thatdarncat]

Interesting that Mike7570's C4 block has the 2 bolt engine mount pattern and my C5 has the 4 bolt hole pattern.
Was C4 to C5 the changeover?
Richard

Yes, the 1965 model year was the changeover. So blocks started to be cast in the summer of calendar year 1964. A lot of new stuff started with the all new chassis 1965 full size Fords.

[frnkeore]

Since you asked. What I'm looking for is free HP and a less expensive build.

4.125 adds 10 cubic inches, over 4.080 and I have a set of 4.125 forged pistons.

Whether or not, in your opinion Ak Miller and others, are wrong, is irrelevant to me, I only know that it was done by many and a usable platform.

The OP was only about when the FE changed to a thin wall casting and at this point, no one seems to know or where to point me, to find out. But, I did ask how much you can bore a late engine and find out that if you bore a later FE to .040, it will not last.

I thought that there might be some technical info from Fords engineering dept available on this forum.

Thank you all, for your input.

[falcongeorge]

I hate to sound crass, but I've heard of the name and he is wrong. 

Yes, we are beating a dead horse, but I would not reinforce to anyone to waste a good 390 block by trying to take it to a 428 bore.  You're much better off with having thick/stable cylinder walls and make up the cubic inches with a different crankshaft, or just flat out make more horsepower with better parts than we had 50 years ago. 

Again, what do you expect to gain from going to the large bore?  A 2.190/2.200" intake valve will work perfectly well on a 4.080" bore size and make big horsepower to boot.

heres the thing, Brent and I basically disagree on this, my position is, if you are smart about it, careful and systematic in your approach, and willing to go to a LOT of effort to hunt up the right block and then sonic test it, you can build a good 4.13 bore FE from SOME (very bloody few) 390 blocks. Brents position is, and in his place as a professional engine builder that is going to send this out the door under the arm of a customer who has paid him a substantial sum, I understand his trepidation, that its not worth it.
The real irony is, you seem to be discounting what BOTH of us are telling you, and feel that, in spite of looking at a couple of sonic maps of early 390 blocks, and Heo telling you that he had an early block that had a thin spot at +.060, you are INSISTENT that NONE of us know what the hell we are talking about, based on a 50 year old article in Hot Rod Magazine.
Now go back to my first sentence, where I mention being "careful and systematic"...do you see why both Brent and I might see a problem here? Probably not...

[blykins]

Since you asked. What I'm looking for is free HP and a less expensive build.

4.125 adds 10 cubic inches, over 4.080 and I have a set of 4.125 forged pistons.

Whether or not, in your opinion Ak Miller and others, are wrong, is irrelevant to me, I only know that it was done by many and a usable platform.

The OP was only about when the FE changed to a thin wall casting and at this point, no one seems to know or where to point me, to find out. But, I did ask how much you can bore a late engine and find out that if you bore a later FE to .040, it will not last.

I thought that there might be some technical info from Fords engineering dept available on this forum.

Thank you all, for your input.

10 cubes is only about 12-13 hp.  Not really worth the effort. 

[plovett]

Brent is simply right.  The gains from a few thousandths larger bore size are probably not even measurable.   The destruction from a cylinder wall a few thousandths too thin is VERY measurable.

JMO,

paulie

[plovett]

10 cubes is only about 12-13 hp.  Not really worth the effort.

See...I don't agree it is even that much.  I would love to see a back to back test with only 10 cubes difference.  Never seen one. But he is still right about the core issue.

JMO,

paulie

[falcongeorge]

Since you asked. What I'm looking for is free HP and a less expensive build.

4.125 adds 10 cubic inches, over 4.080 and I have a set of 4.125 forged pistons.

Whether or not, in your opinion Ak Miller and others, are wrong, is irrelevant to me, I only know that it was done by many and a usable platform.

The OP was only about when the FE changed to a thin wall casting and at this point, no one seems to know or where to point me, to find out. But, I did ask how much you can bore a late engine and find out that if you bore a later FE to .040, it will not last.

I thought that there might be some technical info from Fords engineering dept available on this forum.

Thank you all, for your input.

10 cubes is only about 12-13 hp.  Not really worth the effort.

Whats 13 cfm@.500 lift worth? Now, add that to the 12-13 hp from the extra 10 ci, and all of a sudden, its 20-25 hp. Because that's the difference in intake port flow I saw on my bench just by switching from a 4.03  bore fixture to a 4.155 bore fixture on a brand X head. That little test happened because several of us noticed that the flow numbers on some of the RHS heads a few years back looked a little "happy", and that the published flow numbers were obtained on a 4.155 bore fixture. Everything affects something else.
But the fact is, anybody that thinks that what he reads in the magazines is God-given gospel, and is going to ignore 2 sonic maps, and everything else that's been posted here, is in over his head boring a 390 block to 4.13. Sorry, that's just the way it is. Man, if I had a dollar for every piece of pure, unadulterated horsecrap I have read in the magazines over the years, I wouldn't NEED to worry about boring a 390 block to 4.13, I'd be able to buy a BBM block on the proceeds...

[thatdarncat]

I just went to the garage and popped a core plug from a EDC-6015-C 1958 model year block I have. Date code is “7 0 B”, which is 1957 October 2nd. So a pretty early FE. A 1/4” ( 16/64” ) drill bit fits totally loose between the cylinders, the same as pretty much every other 352-390. You could easily get 17/64” or 18/64” in there. I’m sorry, there was no “switch” to thin wall cast FE’s, they’ve been the same since the start. Many years ago I used to part out ‘58 FE’s to get the EDC heads & adjustable rockers, I never saw a thick cylinder ‘58 FE. You’re getting good info from everyone, I’m sorry it wasn’t what you wanted to hear. Like the guys said, occasionally you find an anomaly, but it’s darn rare.





 

[falcongeorge]

You’re getting good info from everyone, I’m sorry it wasn’t what you wanted to hear.

And that's the crux of the matter, right there. I was thinking about digging out the original article in Hot Rod magazine in late '57, when they wrote about the introduction of the FE series, and bragged about how it was a new-fangled thin-wall casting, but I didn't think there was any point, as "it wasn’t what he wanted to hear".

[plovett]

Since you asked. What I'm looking for is free HP and a less expensive build.

4.125 adds 10 cubic inches, over 4.080 and I have a set of 4.125 forged pistons.

Whether or not, in your opinion Ak Miller and others, are wrong, is irrelevant to me, I only know that it was done by many and a usable platform.

The OP was only about when the FE changed to a thin wall casting and at this point, no one seems to know or where to point me, to find out. But, I did ask how much you can bore a late engine and find out that if you bore a later FE to .040, it will not last.

I thought that there might be some technical info from Fords engineering dept available on this forum.

Thank you all, for your input.

10 cubes is only about 12-13 hp.  Not really worth the effort.

Whats 13 cfm@.500 lift worth? Now, add that to the 12-13 hp from the extra 10 ci, and all of a sudden, its 20-25 hp. Because that's the difference in intake port flow I saw on my bench just by switching from a 4.03  bore fixture to a 4.155 bore fixture on a brand X head.

13 cfm is worth a lot.  10 cid, not so much.  Bore size and cfm are not the same as displacement.

JMO,

paulie

[plovett]

Answer to the original question is, bore as little as possible.  It is that simple.

paulie

[falcongeorge]

Since you asked. What I'm looking for is free HP and a less expensive build.

4.125 adds 10 cubic inches, over 4.080 and I have a set of 4.125 forged pistons.

Whether or not, in your opinion Ak Miller and others, are wrong, is irrelevant to me, I only know that it was done by many and a usable platform.

The OP was only about when the FE changed to a thin wall casting and at this point, no one seems to know or where to point me, to find out. But, I did ask how much you can bore a late engine and find out that if you bore a later FE to .040, it will not last.

I thought that there might be some technical info from Fords engineering dept available on this forum.

Thank you all, for your input.

10 cubes is only about 12-13 hp.  Not really worth the effort.

Whats 13 cfm@.500 lift worth? Now, add that to the 12-13 hp from the extra 10 ci, and all of a sudden, its 20-25 hp. Because that's the difference in intake port flow I saw on my bench just by switching from a 4.03  bore fixture to a 4.155 bore fixture on a brand X head.

13 cfm is worth a lot.  10 cid, not so much.  Bore size and cfm are not the same as displacement.

JMO,

paulie

go back and read what I posted and you just quoted.13 cfm isn't "JMO" or a wild-assed guess, that's what the flow bench test SHOWED when I tested the same head on a .125 larger bore fixture, no other changes. Im posting tested results, not supposition or guesswork. Getting the cylinder wall moved back from the flow cone around the valve probably does MORE than the 10 cid, and THATS the point of the whole exercise. I'm done here.

[cammerfe]

there are a few 390 blocks around that will go +.080 and still be thick enough, but they are not common, and to go out and hunt one down is probably an exercise in masochism, if not futility. If you are really determined, you can pre-sort them with the allen wrench test, but you will still need to sonic test any potential candidates, and if they are pitted on the water jacket side, you can still be in trouble. Brent alluded to the primary reason to do this, unshrouding a 2.19 intake valve. Its always about the cylinder heads.

You can take a look here as well, starting at reply #2. I wouldn't even consider trying to take any OEM FE block to +.125.

http://fepower.net/simplemachinesforum/index.php?topic=7778.0

I was part of the 'action' on one of the first dozen '68 CJ Mustangs. We flew to Romy Hammes Ford in South Bend to pick it up and drove it back to Detroit. Part of the build-up was to create an engine using the heads and crank, but we were told to find a good 390 block and use it as the basis for the new engine. There was, at the time enough difference in block weight to make it a good idea for the class---Super 'E' automatic. We must have gone through about a dozen to find one that made sense to use---and that was 1968. Back about '03, I pulled a '63 330-390 (PI) engine out of the corner of my garage and went through it. If I had gone to 4.13 on it, there were a couple cylinders that would have had .080 spots in them. We took it out to 4.080 and called it good.

KS

[blykins]

Since you asked. What I'm looking for is free HP and a less expensive build.

4.125 adds 10 cubic inches, over 4.080 and I have a set of 4.125 forged pistons.

Whether or not, in your opinion Ak Miller and others, are wrong, is irrelevant to me, I only know that it was done by many and a usable platform.

The OP was only about when the FE changed to a thin wall casting and at this point, no one seems to know or where to point me, to find out. But, I did ask how much you can bore a late engine and find out that if you bore a later FE to .040, it will not last.

I thought that there might be some technical info from Fords engineering dept available on this forum.

Thank you all, for your input.

10 cubes is only about 12-13 hp.  Not really worth the effort.

Whats 13 cfm@.500 lift worth? Now, add that to the 12-13 hp from the extra 10 ci, and all of a sudden, its 20-25 hp. Because that's the difference in intake port flow I saw on my bench just by switching from a 4.03  bore fixture to a 4.155 bore fixture on a brand X head. That little test happened because several of us noticed that the flow numbers on some of the RHS heads a few years back looked a little "happy", and that the published flow numbers were obtained on a 4.155 bore fixture. Everything affects something else.
But the fact is, anybody that thinks that what he reads in the magazines is God-given gospel, and is going to ignore 2 sonic maps, and everything else that's been posted here, is in over his head boring a 390 block to 4.13. Sorry, that's just the way it is. Man, if I had a dollar for every piece of pure, unadulterated horsecrap I have read in the magazines over the years, I wouldn't NEED to worry about boring a 390 block to 4.13, I'd be able to buy a BBM block on the proceeds...

How much power do you lose because the bores are now weaker and you’ve lost some ring seal???  How much flow do you gain on a bore size that's relative to the discussion that we're having here?  Going from a 4.030" bore to a 4.155" is a huge difference and is a lot greater than the difference between a 4.080/4.09/4.100" and a 4.130". 

I’ve ruined at least two 390 blocks that sonic’d well, trying to go to 4.130”.  I’ve also made over 540 hp with a 4.080” bore 390 and some Trick Flow heads with 2.190” valves, on pump gas, with a hydraulic roller, not going over 6000 rpm. 

Tell ya what, you all can go on thinking you’re big power makers with your extra bore size, but just don’t ruin all the 390 block cores.  Save some for the rest of us.....

Little bit of jest there, little bit of seriousness.  All in fun. 

[64PI]

I have one of those "unicorn" 390's from a dump truck with a C scratch on the back. I got it at .030" over, put 2 .090" wall sleeves in it and never hit water. I run the block .060" over and still half filled it for piece of mind.

I had a '64 390 that I bored .020" over (no fill) and it split from the center cam bore to the cylinder on a 500hp pull @ 6000rpm on the dyno.

I'm with Brent on this one.  Take minimal amount of material and leave em thick as possible. If you want cubes stroke it. Or buy an aftermarket block. The money your going to pay your machine shop boring .125" over and then putting in sleeves when they hit water can be better spent elsewhere.

Fred

[falcongeorge]

  How much flow do you gain on a bore size that's relative to the discussion that we're having here?  Going from a 4.030" bore to a 4.155" is a huge difference and is a lot greater than the difference between a 4.080/4.09/4.100" and a 4.130". 

[/quote]
Well, as to the question of whether a test based on chevy bore sizes is going to tell the whole story on the FE, fair enough, I tested the two SBC bore sizes because we were trying to get a handle on how much the larger bore fixture inflated RHS published flow numbers, and I think the test gave us a handle on that.
But consider a couple other factors. 1) a 2.19 in a +.030 390 is closer to the cylinder wall than a 2.05 in a 4.03 chevy and 2) And I think this is the big one. The chevy has a 23 deg. valve angle, the FE is 13, so the valve is coming down much straighter towards the bore, so moving the bore away from the edge of the valve is probably going to help flow numbers even more on the FE. Maybe some further testing is in order, its not a big hassle to switch the bore adapters out on a flow bench, and maybe I will try the same test on an FE head some time. I would probably use a 4.03 because I already have one, and the 4.05 isn't much difference, and compare it to a 4.13. Of course, there will probably STILL be bitching, but if the bitchers don't learn anything, well that's the normal order of things.
As I said in post #24, I understand your position and why you wouldn't want to do it on a customers motor, it probably doesn't do down well when they spend the money for a sonic test, half fill, and boring, and after all that you find a porous spot in the cylinder wall, and its junk. That's fine, I get that.
But it IS do-able, I've DONE it. And as I hinted at in my first post, and made clearer in the last post above, its not about the 10 CI, That's not the big gainer, its about moving the cylinder wall away from the flow cone around the intake valve.

[plovett]

How much flow do you gain on a bore size that's relative to the discussion that we're having here?  Going from a 4.030" bore to a 4.155" is a huge difference and is a lot greater than the difference between a 4.080/4.09/4.100" and a 4.130". 

its not about the 10 CI, That's not the big gainer,its about moving the cylinder wall away from the flow cone around the intake valve.

Now you are starting to make sense.

JMO,

paulie

[falcongeorge]

How much flow do you gain on a bore size that's relative to the discussion that we're having here?  Going from a 4.030" bore to a 4.155" is a huge difference and is a lot greater than the difference between a 4.080/4.09/4.100" and a 4.130". 

its not about the 10 CI, That's not the big gainer,its about moving the cylinder wall away from the flow cone around the intake valve.

Now you are starting to make sense.

JMO,

paulie

I don't really consider the opinion of someone who responds to my posts without reading them to have any validity. Thanks.

[plovett]

I read them. I sometimes get angry, too.   No worries. 

paulie

[plovett]

The first 5 words in the first reply to the OP's post were all that were needed. LOL!

JMO,

paulie

[blykins]

Yes, your point is absolutely correct.  There is no incentive for me to spend a ton of time trying to find a block that will go that large.  Even if it did make a difference, it's a lot of wheel-spinning.  I'd most likely tell a customer to find a 428 block if they want that bore size that bad, or spend the extra money on the cylinder heads, where the power really is.  I'm perfectly content shoving a 2.190" valve up against the cylinder wall in a 390 to make as much hp as most guys were making with 482's, 10 years ago.   The intake valve clearance isn't as detrimental as what you think; but the exhaust valve will get close quick if it's too big.

Now, how about that ring seal loss?   

[falcongeorge]

there are a few 390 blocks around that will go +.080 and still be thick enough, but they are not common, and to go out and hunt one down is probably an exercise in masochism, if not futility. If you are really determined, you can pre-sort them with the allen wrench test, but you will still need to sonic test any potential candidates, and if they are pitted on the water jacket side, you can still be in trouble. Brent alluded to the primary reason to do this, unshrouding a 2.19 intake valve. Its always about the cylinder heads.

You can take a look here as well, starting at reply #2. I wouldn't even consider trying to take any OEM FE block to +.125.

http://fepower.net/simplemachinesforum/index.php?topic=7778.0

Ok Paulie, I'll put the hatchet down. But heres the thing you said "now you are talking sense".
Above is my VERY FIRST POST on this thread. Note the two bolded lines at the end of the first paragraph. Its been what I was saying since I started, three pages back, its all about getting the cylinder wall away from the valve .
Brent and I may not agree, but its clear from his responses that he carefully reads what I say, thinks about it, and then responds to what I have said. That tells me that even though we disagree, he is respecting the points I am making, and thinking about them.
I watched both this thread and the thread on correct wall clearance for TRW L2291's, and I watched and waited for a long time before I responded. In both cases, I was hesitant to respond, because frankly, I am just not interested in entering into pissing matches. This thread is largely about opinions, but in the case of the TRW thread, the info he was getting was just plain wrong, factually incorrect.
I have been on internet automotive forums since the 1990s, and for me, the first thing that goes through my mind when I see a thread like that is "hell, its no skin off my ass if the info this guys getting is crap, and hes going screw his stuff up if he follows it, but if I speak up, theres going to be a pissing match, so I am just going to keep my mouth shut, its not my problem, and I don't need the grief". And I can tell you for a stone cold fact, I know a HELL of a lot of other guys that feel the same way. I know several guys that are VERY EXPERIENCED engine builders, chassis builders, and fabricators who lurk these forums, see all KINDS of totally stupid stuff being repeated over and over again, and just sit back and watch and laugh about it. Hell, its one of our favorite topics when we are sitting in restaurants over coffee.
They take the attitude "Why the hell should I waste my valuable time typing something out when some keyboard commando is going to be blowing smoke up my @$$, just repeating some crap that he read in Car Craft or Yellow Bullet? Theres nothing in it for me, I don't gain anything, and I gotta put up with the grief". And honestly, I am starting to develop the same attitude, I see lots of stuff that just flat out wrong, and I ignore it, because I am not going to gain anything, and its going to trigger a flame war. Who needs it? And we all suffer because it, because it kills off any chance of a respectful exchange of knowledge and experience.
Im not saying you are doing this, its a more extreme example, but hell, its all over the place on the internet, and I can tell you, the MAJORITY of the guys that I respect and learn from will not post ANYTHING on ANY interent forum because of the lack of respectful discourse and discussion.
So the point of all this is, ANYBODY, EVERYBODY, ME INCLUDED, before you go off half-cocked on something you disagree with, 1) make sure you have REALLY read it, and understand it. If you don't, swallow your pride and ask for clarification, maybe you will learn something new and 2) when you respond, realize that there are LOTS of other eyes reading what you say, and based on the nature of your response, they may be thinking "ha, forget this bs, I'll keep my knowledge and experience to myself", and believe me, LOTS of VERY experienced race car builders are reading this stuff and thinking exactly that.

[Drew Pojedinec]

So uhhhh I got some super duper thick wall 390’s for sale

[67428GT500]

The Being '66 was the first year and 70 the last year of the 428 as far as vehicle installed most I looked at to replace my block with that split two cylinders are relatively thin at 4.130. I have sonic checks on four blocks I considered for purchase. The thickest wound up being a 105 D4 block. I have .140- .156 and this is at a 4.155 bore.  One of the lessons learned with the new block is how important it is to bore the block with a torque plate. Charles at Charles machine was showing me that the distortion is usually .005 or more.  Not one of the earlier FE specific book offerings mention this.  Very little about it until Barry's books.
I am going to fire the new engine this weekend.  Hopefully all goes well. It seemed strange to grind the tangs off of the Cleveland mains. I hope all is well there too. Perhaps the cam is the largest concern. Always nerve racking breaking in flat tappet cams.

                                                                                                           -Keith

[Tommy-T]

The Being '66 was the first year and 70 the last year of the 428 as far as vehicle installed most I looked at to replace my block with that split two cylinders are relatively thin at 4.130. I have sonic checks on four blocks I considered for purchase. The thickest wound up being a 105 D4 block. I have .140- .156 and this is at a 4.155 bore.  One of the lessons learned with the new block is how important it is to bore the block with a torque plate. Charles at Charles machine was showing me that the distortion is usually .005 or more.  Not one of the earlier FE specific book offerings mention this.  Very little about it until Barry's books.
I am going to fire the new engine this weekend.  Hopefully all goes well. It seemed strange to grind the tangs off of the Cleveland mains. I hope all is well there too. Perhaps the cam is the largest concern. Always nerve racking breaking in flat tappet cams.

                                                                                                           -Keith

Keith, I wish I was as fortunate as you when I went searching for a thick 390 block. The thickest I found was also a D4TE block. The machine shop sonic'd it and said it would be thicker than .100 everywhere after a 4.130 bore. Got it done and in the meantime got an Ebay sonic checker. Naturally, when I sonic'd it myself after the boring, I found a place .079 was the thinnest, and 3 other spots below .090. Filled it to the water pump holes and am going to run it. Wouldn't have started this project if I didn't already have the pistons and crank.
No more .080 over 390 blocks for me. I do believe the "thickies" are out there...but really hard to find.
Good luck on the cam break-in.

[falcongeorge]

The Being '66 was the first year and 70 the last year of the 428 as far as vehicle installed most I looked at to replace my block with that split two cylinders are relatively thin at 4.130. I have sonic checks on four blocks I considered for purchase. The thickest wound up being a 105 D4 block. I have .140- .156 and this is at a 4.155 bore.  One of the lessons learned with the new block is how important it is to bore the block with a torque plate. Charles at Charles machine was showing me that the distortion is usually .005 or more.  Not one of the earlier FE specific book offerings mention this.  Very little about it until Barry's books.
I am going to fire the new engine this weekend.  Hopefully all goes well. It seemed strange to grind the tangs off of the Cleveland mains. I hope all is well there too. Perhaps the cam is the largest concern. Always nerve racking breaking in flat tappet cams.

                                                                                                           -Keith

Keith, I wish I was as fortunate as you when I went searching for a thick 390 block. The thickest I found was also a D4TE block. The machine shop sonic'd it and said it would be thicker than .100 everywhere after a 4.130 bore. Got it done and in the meantime got an Ebay sonic checker. Naturally, when I sonic'd it myself after the boring, I found a place .079 was the thinnest, and 3 other spots below .090. Filled it to the water pump holes and am going to run it. Wouldn't have started this project if I didn't already have the pistons and crank.
No more .080 over 390 blocks for me. I do believe the "thickies" are out there...but really hard to find.
Good luck on the cam break-in.

Very little mention on here of WHERE the thick or thin spots are, which is vitally important. .079 between the bores? Meh, who cares? .079 on the minor thrust side? I'd be pretty nervous. .079 on the major thrust side? Its scrap.
The other question I would be asking myself, is my ebay sonic tester as accurate as the one the machine shop used. I realize they pinged it before they bored, and you pinged it afterwards, but that's still a question worth asking. Is it possible to get them to re-test the area in question against your tester?

[thatdarncat]

The Being '66 was the first year and 70 the last year of the 428 as far as vehicle installed most I looked at to replace my block with that split two cylinders are relatively thin at 4.130. I have sonic checks on four blocks I considered for purchase. The thickest wound up being a 105 D4 block. I have .140- .156 and this is at a 4.155 bore.  One of the lessons learned with the new block is how important it is to bore the block with a torque plate. Charles at Charles machine was showing me that the distortion is usually .005 or more.  Not one of the earlier FE specific book offerings mention this.  Very little about it until Barry's books.
I am going to fire the new engine this weekend.  Hopefully all goes well. It seemed strange to grind the tangs off of the Cleveland mains. I hope all is well there too. Perhaps the cam is the largest concern. Always nerve racking breaking in flat tappet cams.

                                                                                                           -Keith

Keith, I wish I was as fortunate as you when I went searching for a thick 390 block. The thickest I found was also a D4TE block. The machine shop sonic'd it and said it would be thicker than .100 everywhere after a 4.130 bore. Got it done and in the meantime got an Ebay sonic checker. Naturally, when I sonic'd it myself after the boring, I found a place .079 was the thinnest, and 3 other spots below .090. Filled it to the water pump holes and am going to run it. Wouldn't have started this project if I didn't already have the pistons and crank.
No more .080 over 390 blocks for me. I do believe the "thickies" are out there...but really hard to find.
Good luck on the cam break-in.

Very little mention on here of WHERE the thick or thin spots are, which is vitally important. .079 between the bores? Meh, who cares? .079 on the minor thrust side? I'd be pretty nervous. .079 on the major thrust side? Its scrap.
The other question I would be asking myself, is my ebay sonic tester as accurate as the one the machine shop used. I realize they pinged it before they bored, and you pinged it afterwards, but that's still a question worth asking. Is it possible to get them to re-test the area in question against your tester?

I’ve seen a 427 split a cylinder wall between cylinders at around .100. Personally I wouldn’t dismiss that location.

Recently I spot tested a 390 with my eBay sonic tester that I had previously tested by a professional machine shop - all the readings I got were within .000 to .003 of what the shop noted on the sheet, I was pleasantly surprised by that, considering I may not have had my transducer on the exact same spot. It’s common practice of course to check your sonic tester on a spot on the block you can actually measure with a micrometer or caliper, so it’s easy to see if your eBay sonic tester is accurate. One nice thing about having your own tester is the ability to test as many places as you want, one FE block I was playing around with this spring I noticed a small area significantly thinner than the surrounding areas, and outside of the normal 0, 90, 180, 270 degree areas you check. Would it be an issue, maybe not, but good to have the info.

[jayb]

Late to this thread, but I have a few things to add.  When I started hot rodding in 1976, Ak Miller was quite the revered name in Ford circles, and I grabbed every bit of information I could get that he wrote, including some articles on running 105 octane propane and turbocharging FEs, which I found quite interesting.

One of the articles Ak wrote back in the day showed how to "wake up" a 390 using an Offenhauser 360 degree manifold with a Carter Thermoquad carb.  Sometime in the mid 1980s I grabbed one of those manifolds at a swap meet, and stuck it aside for a future build.

Fast forward to 2005, when I started doing the intake manifold testing that resulted in my book.  I had high hopes for that Offy 360 manifold; it looked different than everything else, and Ak said it really worked.  However, to call the manifold's performance sub-par would be being kind.  It was one of the worst manifolds I tested.  That intake wasn't going to wake up any 390, more like put it to sleep!

All my respect for Ak Miller pretty much went out the window at that point, because no matter what dyno mule I put that intake on, or what carb I used, it did not perform well, certainly not as well as the Ford performance intakes that were available at the time.  A 428CJ intake or a PI intake would best that manifold by 30-40 horsepower on most engines.  Maybe Ak had an arrangement with Offy or something, and wrote the article for publicity.  I referenced the article in the Offy 360 manifold section of my book, although I didn't mention Ak's name, referring to him only as a "well respected Ford engine expert".

In any case, that experience makes Ak Miller's advice pretty suspect in my opinion.  Also, regarding weight of a 390, my 390 stroker with aluminum water pump, aluminum heads and intake, steel tube headers, and an aluminum flywheel weighed just under 500 pounds.  No starter, no alternator, but everything else required to run the engine on the dyno was included.  There was even oil in the oil pan.  Probably add about 50 pounds to go back to cast iron heads.

I happen to have a 391 truck block here with the "428" cast in the water jackets, and it sonics so well that I wouldn't be afraid to take it to 4.16 if it needed it.  I've never seen another 390 block close to as thick as that one.  The advice to the original poster to overbore as little as possible is spot-on, in my opinion.

[blykins]

The Being '66 was the first year and 70 the last year of the 428 as far as vehicle installed most I looked at to replace my block with that split two cylinders are relatively thin at 4.130. I have sonic checks on four blocks I considered for purchase. The thickest wound up being a 105 D4 block. I have .140- .156 and this is at a 4.155 bore.  One of the lessons learned with the new block is how important it is to bore the block with a torque plate. Charles at Charles machine was showing me that the distortion is usually .005 or more.  Not one of the earlier FE specific book offerings mention this.  Very little about it until Barry's books.
I am going to fire the new engine this weekend.  Hopefully all goes well. It seemed strange to grind the tangs off of the Cleveland mains. I hope all is well there too. Perhaps the cam is the largest concern. Always nerve racking breaking in flat tappet cams.

                                                                                                           -Keith

Keith, I wish I was as fortunate as you when I went searching for a thick 390 block. The thickest I found was also a D4TE block. The machine shop sonic'd it and said it would be thicker than .100 everywhere after a 4.130 bore. Got it done and in the meantime got an Ebay sonic checker. Naturally, when I sonic'd it myself after the boring, I found a place .079 was the thinnest, and 3 other spots below .090. Filled it to the water pump holes and am going to run it. Wouldn't have started this project if I didn't already have the pistons and crank.
No more .080 over 390 blocks for me. I do believe the "thickies" are out there...but really hard to find.
Good luck on the cam break-in.

Very little mention on here of WHERE the thick or thin spots are, which is vitally important. .079 between the bores? Meh, who cares? .079 on the minor thrust side? I'd be pretty nervous. .079 on the major thrust side? Its scrap.
The other question I would be asking myself, is my ebay sonic tester as accurate as the one the machine shop used. I realize they pinged it before they bored, and you pinged it afterwards, but that's still a question worth asking. Is it possible to get them to re-test the area in question against your tester?

I’ve seen a 427 split a cylinder wall between cylinders at around .100. Personally I wouldn’t dismiss that location.

Exactly.  It may not be a thrust surface, but a thin cylinder on any "side" is weak....also gets back to that ring seal point......a weak cylinder will flex.

Tommy T, your intuition to fill the block was spot on. 

[falcongeorge]

The Being '66 was the first year and 70 the last year of the 428 as far as vehicle installed most I looked at to replace my block with that split two cylinders are relatively thin at 4.130. I have sonic checks on four blocks I considered for purchase. The thickest wound up being a 105 D4 block. I have .140- .156 and this is at a 4.155 bore.  One of the lessons learned with the new block is how important it is to bore the block with a torque plate. Charles at Charles machine was showing me that the distortion is usually .005 or more.  Not one of the earlier FE specific book offerings mention this.  Very little about it until Barry's books.
I am going to fire the new engine this weekend.  Hopefully all goes well. It seemed strange to grind the tangs off of the Cleveland mains. I hope all is well there too. Perhaps the cam is the largest concern. Always nerve racking breaking in flat tappet cams.

                                                                                                           -Keith

Keith, I wish I was as fortunate as you when I went searching for a thick 390 block. The thickest I found was also a D4TE block. The machine shop sonic'd it and said it would be thicker than .100 everywhere after a 4.130 bore. Got it done and in the meantime got an Ebay sonic checker. Naturally, when I sonic'd it myself after the boring, I found a place .079 was the thinnest, and 3 other spots below .090. Filled it to the water pump holes and am going to run it. Wouldn't have started this project if I didn't already have the pistons and crank.
No more .080 over 390 blocks for me. I do believe the "thickies" are out there...but really hard to find.
Good luck on the cam break-in.

Very little mention on here of WHERE the thick or thin spots are, which is vitally important. .079 between the bores? Meh, who cares? .079 on the minor thrust side? I'd be pretty nervous. .079 on the major thrust side? Its scrap.
The other question I would be asking myself, is my ebay sonic tester as accurate as the one the machine shop used. I realize they pinged it before they bored, and you pinged it afterwards, but that's still a question worth asking. Is it possible to get them to re-test the area in question against your tester?

I’ve seen a 427 split a cylinder wall between cylinders at around .100. Personally I wouldn’t dismiss that location.

Recently I spot tested a 390 with my eBay sonic tester that I had previously tested by a professional machine shop - all the readings I got were within .000 to .003 of what the shop noted on the sheet, I was pleasantly surprised by that, considering I may not have had my transducer on the exact same spot. It’s common practice of course to check your sonic tester on a spot on the block you can actually measure with a micrometer or caliper, so it’s easy to see if your eBay sonic tester is accurate. One nice thing about having your own tester is the ability to test as many places as you want, one FE block I was playing around with this spring I noticed a small area significantly thinner than the surrounding areas, and outside of the normal 0, 90, 180, 270 degree areas you check. Would it be an issue, maybe not, but good to have the info.

good info on the ebay sonic testers. I have thought about buying one a few times, but at my age, I will probably just be building the stuff I have and not acquiring much in the way of new blocks, I am not sure how much use I would get out of it.

[falcongeorge]

The Being '66 was the first year and 70 the last year of the 428 as far as vehicle installed most I looked at to replace my block with that split two cylinders are relatively thin at 4.130. I have sonic checks on four blocks I considered for purchase. The thickest wound up being a 105 D4 block. I have .140- .156 and this is at a 4.155 bore.  One of the lessons learned with the new block is how important it is to bore the block with a torque plate. Charles at Charles machine was showing me that the distortion is usually .005 or more.  Not one of the earlier FE specific book offerings mention this.  Very little about it until Barry's books.
I am going to fire the new engine this weekend.  Hopefully all goes well. It seemed strange to grind the tangs off of the Cleveland mains. I hope all is well there too. Perhaps the cam is the largest concern. Always nerve racking breaking in flat tappet cams.

                                                                                                           -Keith

Keith, I wish I was as fortunate as you when I went searching for a thick 390 block. The thickest I found was also a D4TE block. The machine shop sonic'd it and said it would be thicker than .100 everywhere after a 4.130 bore. Got it done and in the meantime got an Ebay sonic checker. Naturally, when I sonic'd it myself after the boring, I found a place .079 was the thinnest, and 3 other spots below .090. Filled it to the water pump holes and am going to run it. Wouldn't have started this project if I didn't already have the pistons and crank.
No more .080 over 390 blocks for me. I do believe the "thickies" are out there...but really hard to find.
Good luck on the cam break-in.

Very little mention on here of WHERE the thick or thin spots are, which is vitally important. .079 between the bores? Meh, who cares? .079 on the minor thrust side? I'd be pretty nervous. .079 on the major thrust side? Its scrap.
The other question I would be asking myself, is my ebay sonic tester as accurate as the one the machine shop used. I realize they pinged it before they bored, and you pinged it afterwards, but that's still a question worth asking. Is it possible to get them to re-test the area in question against your tester?

I’ve seen a 427 split a cylinder wall between cylinders at around .100. Personally I wouldn’t dismiss that location.

Exactly.  It may not be a thrust surface, but a thin cylinder on any "side" is weak....also gets back to that ring seal point......a weak cylinder will flex.

Tommy T, your intuition to fill the block was spot on.

Totally agree on the fill. I didn't want to discourage the poster, but to be honest, I would be hesitant to build a motor that had a .079 spot in a cylinder wall ANYWHERE, filled or not. I know some guys do it, and skate by, but that's pretty bloody thin. You might skate by depending on where, down low between cylinders would be best scenario, but that's awfully thin, regardless. Too bad its already filled, if it were only one cylinder that thin, I would sleeve the hole.

[plovett]

The OP was only about when the FE changed to a thin wall casting and at this point, no one seems to know or where to point me, to find out. But, I did ask how much you can bore a late engine and find out that if you bore a later FE to .040, it will not last.

The answer is the FE never changed to a thin wall casting.  It always was a thin wall casting.  Sure, they are not all exactly the same thickness, but they are all "thin". 

The other answer is bore as little as possible and yes a 0.040" overbore is doable on almost all FE's.

[falcongeorge]

 but they are all "thin". 

[/quote]
Ignorance is bliss, who am I to ruin anyones happiness?

[67428GT500]

He is correct as the FE is considered new technology and a "light weight casting". Certainly you aren't indicating Mr. Lovett is incorrect. They are light weight thin wall castings, as are the 221-302 castings.

[falcongeorge]

Certainly you aren't indicating Mr. Lovett is incorrect.

Yup.

[frnkeore]

I'm a old dog but, can be taught new tricks

I will concede that they are fairly thin wall with the early block measurement of that EDC block (I'll call it .281) by thatdarncat. But, on a well centered core, it would still give you a .112 wall and doable for a 4.125 bore, at least in my day. Sonic testing would have only been a dream, in my early years. Maybe my Unicorn is the '58 Edsel 361 engine, the first 4.05 bore FE.

To that end, yesterday, I did a search of 1958 Ford advertising to see if I could find a reference of the "New Ford Thin Wall technology" I did not find anything that said that. If anyone has any real literature on the '58 FE's new thin wall castings, I would appreciate it being posted. It has to be out there, Ford was never silent about new developments.

I do appreciate everyone input and I am surprised at the length of this thread. I'm a retired  machinist and do like and appereciate the measurements that your giving.



'58 was a big year for Ford, they also came out with the MEL and a new line of truck engines

[blykins]

For crying out loud. 

A lot of Ford engines around this time were thin in the cylinders.   Clevelands were thin at standard bore.  I don't know how many blocks I've sonic tested to see .090-.100" cylinder wall thicknesses with no machine work.  I've seen some that were down around .040-.050".   They got sleeved or filled. 

A lot of 351 Windsor blocks are done at .060", if they go that far.

Just because there are a few 390 blocks out there that will take a large overbore doesn't really mean that it's wise to do it.  In fact, you're not accomplishing anything at all if you do it that way, besides perpetuating 60's thinking of "if it's bigger, it's better".   

Who in the world cares if it was advertised that they were thin or not?  Grab a block, sonic test it, and found out whether or not *that* block is thin because every block is a craps shoot. 

I'll be the first one to say that thick blocks do exist, because I had a '63 390 block that went that far without issue.  However, I wasted 2 to get to that point, and in hind sight, I accomplished ABSOLUTELY NOTHING by taking the one block out to a 4.130" bore.  Going from a 4.08-4.09 bore to a 4.130 bore doesn't open up magical gateways to head flow!  It does nothing but endanger the block's strength by making the cylinders weaker and it opens the block up to really weak spots due to pitting on the back sides of the cylinders that you can't see. 

If you do have a block that could go 4.130" and have plenty of meat left over, think about how rigid the block would be if you didn't do more than a clean-up cut. 

[My427stang]

I am with Brent, some 2 bolt motor mount blocks you can get lucky, but a thick 390 or 428 is a unicorn. I would rather stroke or live with a smaller bore, not worth chasing around for, put more time in other parts

[Gregg]

Common sense answers throughout this thread.  Sometimes people just want to believe what they want.  I can't really imagine a sales campaign of "Look at our new thin wall engine block technology".  Folks may have cared about brand, most cared about price and options, some fuel mileage, some power.  In fact, some may have been put off by the "new fangled" thin wall technology.

[shady]

I rebuilt a mid '70s truck 390 in the early 80s that needed a bore. TRW made 60 over pistons so I figured what the heck, may as well go for the gusto. 500 miles later it hydro-locked. Pulling the heads I saw a split in one of the cyl. walls. I opened the split with a pry bar and couldn't believe how paper thin the wall was. After that, there was no going beyond .030 for me.

[GerryP]

Anyone -who is not me- care to explain exactly what "thin wall" casting is as far as engine blocks is concerned?

Seriously, if cubic inches are your primary concern, you should be building a Lima motor.  Very easy to get over 600 C.I. without even breaking a sweat or your budget.

[Gregg]

From Wikipedia (not the best source, but something)

The FE's thinwall casting production method was innovative and forward-looking in the mid-1950, resulting in lower weight and dramatically reduced production costs. Ford's competitors at the time required thicker castings to mask the flaws and defects that resulted from their processes. Improving quality and allowing thinner walls was accomplished through many engineering improvements, including reducing the number of cores required to cast an engine block. Fewer cores made it easier to assemble the overall mold for casting and reduced the number of potential problems. In the late 1980s when both Ford and GM revamped their V8 offerings, many of the FE's designs and engineering were incorporated in the new engines, including the deep skirt, cross-bolting of the mains and thinwall casting.

[GerryP]

From Wikipedia (not the best source, but something)

In this case, Wiki got it right, Gregg.  But to clarify, the "thin wall" isn't referring to just the cylinder walls, but to all the walls in the block.  This is pan rails, cooling jacket, cylinder walls and everything in the block.

[falcongeorge]

  Grab a block, sonic test it, and found out whether or not *that* block is thin because every block is a craps shoot. 

I'll be the first one to say that thick blocks do exist, because I had a '63 390 block that went that far without issue.  However, I wasted 2 to get to that point, and in hind sight, I accomplished ABSOLUTELY NOTHING by taking the one block out to a 4.130" bore.  Going from a 4.08-4.09 bore to a 4.130 bore doesn't open up magical gateways to head flow!  It does nothing but endanger the block's strength by making the cylinders weaker and it opens the block up to really weak spots due to pitting on the back sides of the cylinders that you can't see. 

If you do have a block that could go 4.130" and have plenty of meat left over, think about how rigid the block would be if you didn't do more than a clean-up cut.

hahaha, Brent knows something the rest of you guys don't. He aint gonna say it right out, and that suits me just fine, I aint talking anymore either. Someone once said that "George does not suffer fools kindly". Guilty as charged.

[blykins]

  Grab a block, sonic test it, and found out whether or not *that* block is thin because every block is a craps shoot. 

I'll be the first one to say that thick blocks do exist, because I had a '63 390 block that went that far without issue.  However, I wasted 2 to get to that point, and in hind sight, I accomplished ABSOLUTELY NOTHING by taking the one block out to a 4.130" bore.  Going from a 4.08-4.09 bore to a 4.130 bore doesn't open up magical gateways to head flow!  It does nothing but endanger the block's strength by making the cylinders weaker and it opens the block up to really weak spots due to pitting on the back sides of the cylinders that you can't see. 

If you do have a block that could go 4.130" and have plenty of meat left over, think about how rigid the block would be if you  didn't do more than a clean-up cut.

hahaha, Brent knows something the rest of you guys don't. He aint gonna say it right out, and that suits me just fine, I aint talking anymore either. Someone once said that "George does not suffer fools kindly". Guilty as charged.

Explain to me what I’m not going to say because I’m interested in hearing it.

[C6AE]

I built an A scratch 428 that took .060 just fine, but I wouldn't bet on another.

[WConley]

It's also notable that another old-school authority, Carl Holbrook, went to all of the trouble of sleeving and furnace brazing all eight cylinders on brand new CJ blocks for some of his race engines!  Having dead-nuts uniform cylinder walls was important to him for optimal ring seal.

If a guy as knowledgeable as Carl would go to all of that trouble, there's something to be said for keeping those walls as thick as possible.  As other smart guys here have said, the modern stroker kits and good heads are where it's at.

- Bill

[Drew Pojedinec]

I think most 390's are boring.

There, I said it.

[jayb]

LOL!  Well, I was thinking it....

[falcongeorge]

This conversation has continued on off-forum and some snickering has ensued. Apparently another FE Power member within about 20 miles of the "Area 51 Garage" had one of these "nonexistent" blocks ,and he mentioned to me that theres a third one (all three are early-mid seventies service blocks),  within 5 miles of my place. Im gonna try to find out if I can get a look at it, and hopefully stick a drill bit between the cores. But don't worry, we'll keep the results to ourselves, I don't wanna cause anymore emotional trauma.
Geez, three "non-existant" blocks in a 20 mile radius! Whoda thunk??!! Must be a disturbance in the gravitational field or something! Don't mind me, carry on with "all 390's are thinwall castings" internet groupthink, some of us are enjoying this...

[My427stang]

A drill bit test isn't going to prove much, the question is condition of cylinders and core shift.  The 2 bolt motor mount blocks seem a little more consistent, but after that, they are all over the map.  Last fall I turned down a 428 standard bore  irrigation motor for the hyd roller build in the dyno section because four on one back were "over and up" and I didn't trust the block at .030 and 500 hp. 

Of course if no-one checks, any block might work!

[plovett]

Well, thick and thin are subjective terms.  That's why I put thin in quotes.  There are some engines that can be bored 0.125" over and still have good cylinder wall thickness.  I would consider them "thick".  I think all FE's are "thin".  Sure, there is a lot of variation, but none are what I would call "thick".   It is not a criticism.  It is just a design feature of the block. 

JMO,

paulie

[plovett]

Let me clarify.    I don't think any factory FE blocks are "thick".  Aftermarket blocks are a different story.

JMO,

paulie

[falcongeorge]

A drill bit test isn't going to prove much, the question is condition of cylinders and core shift.  The 2 bolt motor mount blocks seem a little more consistent, but after that, they are all over the map.  Last fall I turned down a 428 standard bore  irrigation motor for the hyd roller build in the dyno section because four on one back were "over and up" and I didn't trust the block at .030 and 500 hp. 

Of course if no-one checks, any block might work!

I guess its not surprising a bunch of guys that have no idea how to find these blocks think that they don't exist.

[Gregwill16]

A drill bit test isn't going to prove much, the question is condition of cylinders and core shift.  The 2 bolt motor mount blocks seem a little more consistent, but after that, they are all over the map.  Last fall I turned down a 428 standard bore  irrigation motor for the hyd roller build in the dyno section because four on one back were "over and up" and I didn't trust the block at .030 and 500 hp. 

Of course if no-one checks, any block might work!

I guess its not surprising a bunch of guys that have no idea how to find these blocks think that they don't exist.

Falcongeorge you sound like a very experienced and knowledgeable individual but I wouldn't downllay the knowledge and experience of others on this forum. They are simply being honest and expressing their own knowledge and experiences, in hopes of saving someone alot of grief. Also preventing someone of thinking they have something that they really don't and throwing a ton of money at something that could end in failure.

[blykins]

A drill bit test isn't going to prove much, the question is condition of cylinders and core shift.  The 2 bolt motor mount blocks seem a little more consistent, but after that, they are all over the map.  Last fall I turned down a 428 standard bore  irrigation motor for the hyd roller build in the dyno section because four on one back were "over and up" and I didn't trust the block at .030 and 500 hp. 

Of course if no-one checks, any block might work!

I guess its not surprising a bunch of guys that have no idea how to find these blocks think that they don't exist.

No one is saying they don’t exist.

We are all saying it’s not prudent to bore the snot out of them.  Maybe jay will step back and put this thread out of its misery.

[Barry_R]

I guess its not surprising a bunch of guys that have no idea how to find these blocks think that they don't exist.

I have only checked about 100 per year for the last decade or so.

I have found definitely under ten - maybe under five - that I considered truly safe as 4.130 candidates.
One of them had the "C" scratch in the bell and a distributor bushing.

I guess I am not looking hard enough...

[falcongeorge]

A drill bit test isn't going to prove much, the question is condition of cylinders and core shift.  The 2 bolt motor mount blocks seem a little more consistent, but after that, they are all over the map.  Last fall I turned down a 428 standard bore  irrigation motor for the hyd roller build in the dyno section because four on one back were "over and up" and I didn't trust the block at .030 and 500 hp. 

Of course if no-one checks, any block might work!

I guess its not surprising a bunch of guys that have no idea how to find these blocks think that they don't exist.

Falcongeorge you sound like a very experienced and knowledgeable individual but I wouldn't downllay the knowledge and experience of others on this forum. They are simply being honest and expressing their own knowledge and experiences, in hopes of saving someone alot of grief. Also preventing someone of thinking they have something that they really don't and throwing a ton of money at something that could end in failure.

You are correct that I am mocking, early on I was sharing usable info, now I have resorted to mockery rather than sharing info, in fact, I am deliberately withholding that info. Earlier on, I had posted a fair amount of solid, hard-core stuff on what the thick blocks are all about, when they were produced, and how to identify them. When it turned into the usual internet forum dogpile, I went back and carefully edited any usable information that would help guys find these blocks, as they aren't interested in that.
They don't have any of these blocks, and haven't seen any, because they don't have the required knowledge to identify them.
And the nature of the typical post-modernist mob is so hubristic, that if THEY dont know about something, then it doesn't exist. This is the predominant groupthink on internet forums. The line of reasoning (if you can call it that) goes like this. "I might not know much about the information being presented, but most of the people posting here are saying this information is wrong, if I join in, I can piggyback on this, and appear more knowledgeable than I actually am. Even if the people I am agreeing with are incorrect, the sheer weight of numbers lends credence, and I can safely ride on the coattails of that". I alluded to this on page three in post #43, but naturally, it had zero effect, and didn't cause anyone to pause and reflect for even a moment. So it really shouldn't be surprising that I am mocking them rather than sharing information. Sharing that information would be a wasted effort, due to their hubris.
So, especially in light of the fact that I have a late 390 block that is cast on 428 cores sitting less than 100' from me as I type this, it shouldn't be surprising that I choose to mock, rather than inform. Taking the low ground? Well yes, I am, but then I am a notorious iconoclast, so...
A quote from a famous American iconoclast, I think it applies rather well in the context of critiquing the post modernist groupthink that dominates internet forums
"Whenever you find yourself on the side of the majority, it is time to pause and reflect."
Mark Twain


Hubris (/ˈhjuːbrɪs/, from ancient Greek ὕβρις) describes a personality quality of extreme or foolish pride or dangerous overconfidence,[1] often in combination with (or synonymous with) arrogance.[2] In its ancient Greek context, it typically describes behavior that defies the norms of behavior or challenges the gods, and which in turn brings about the downfall, or nemesis, of the perpetrator of hubris. The adjectival form of the noun hubris is "hubristic".

Hubris is usually perceived as a characteristic of an individual rather than a group, although the group the offender belongs to may suffer collateral consequences from the wrongful act. Hubris often indicates a loss of contact with reality and an overestimation of one's own competence, accomplishments or capabilities

FWIW, I am not at all angry, in fact, I am rather enjoying this, I hope that is coming across in my posts.
To show a little goodwill, I will expand on my flippant response to My427stangs hubris. The drill bit test is vitally important, it tells you what cores the block is cast on. This is a field test, it helps you to decide whether it is worthwhile to haul the dirty chunk of cast iron laying in front of you into the machine shop for a sonic test, or to leave it where it lays. This test is vital even if you intend to build a +030 390 out of said chunk of cast iron, as blocks that will accept a 1/4" or 3/8" bit aren't even suitable for that.
So there you go, just so this debacle isn't a total waste of bandwidth. Of course, the hubris of most members of any given internet dogpile will prevent them from even utilizing this little tidbit of information. Carry on...

[falcongeorge]

I guess its not surprising a bunch of guys that have no idea how to find these blocks think that they don't exist.

I have only checked about 100 per year for the last decade or so.

I have found definitely under ten - maybe under five - that I considered truly safe as 4.130 candidates.
One of them had the "C" scratch in the bell and a distributor bushing.

I guess I am not looking hard enough...

Barry, the fact that you have found ANY, even if it were one, proves my point. They do exist, and those that are saying they don't are full of $#*^. And as I said in the other thread, mine does not have a distributor bushing.

[falcongeorge]

I guess its not surprising a bunch of guys that have no idea how to find these blocks think that they don't exist.

No one is saying they don’t exist.

We are all saying it’s not prudent to bore the snot out of them.  Maybe jay will step back and put this thread out of its misery.
[/quote]
Brent, that's what YOU are saying, and I haven't said you are wrong, maybe that I don't 100% agree, but I understand and respect your position. Plovett and MANY others have said "All 390's are thinwall". Do I need to post the definition of "all"?

[falcongeorge]

there are a few 390 blocks around that will go +.080 and still be thick enough, but they are not common, and to go out and hunt one down is probably an exercise in masochism, if not futility.you will need to sonic test any potential candidates, and if they are pitted on the water jacket side, you can still be in trouble. Brent alluded to the primary reason to do this, unshrouding a 2.19 intake valve. Its always about the cylinder heads.
 I wouldn't even consider trying to take any OEM FE block to +.125.

My very first post. Looks like Barry, Brent and I are all saying pretty much the same thing. As to the "All 390s are thinwall" keyboard commandos, well....

[Yellow Truck]

Brent, that's what YOU are saying, and I haven't said you are wrong, maybe that I don't 100% agree, but I understand and respect your position. Plovett and MANY others have said "All 390's are thinwall". Do I need to post the definition of "all"?

I agree with others that this thread has run its useful course, but I will point out that the term "thin wall" is being used to describe both a method of manufacturing as well as a condition of an individual block. The original question was "when did Ford start using thin wall casting for the FE?", and I am paraphrasing. The consensus seems to be that they were always cast using what was considered "thin wall" technique.

The second use of the term is "are 390 cylinder walls too thin to take a bore bigger than 4.08?", and the consensus seems to be that most are too thin and a very few are not. These two uses are very different in meaning.

The debate seems to be whether or not a 390 casting, or a 428, that has sufficient thickness to bore it out beyond a clean up should in fact be so bored. I believe the consensus on the last question would be - if you are fortunate enough to find such a unicorn, do with it what you want but most of the builders here would do the least possible to protect the engine since there is little to be gained and much to be lost. 

[MeanGene]

I remember what our local, quite sharp dealership parts guy told us in the mid-70's, that if you bought a 428 service block then, you would get a bored out 391 block, as they were using one service casting based on the 428, but only (normally) bored to 4.05- which would of course be a cost savings over casting different blocks for service use when not necessary. Actually makes perfect fiscal sense, and would explain some 360s and 390s with "thick" walls

[falcongeorge]

I remember what our local, quite sharp dealership parts guy told us in the mid-70's, that if you bought a 428 service block then, you would get a bored out 391 block, as they were using one service casting based on the 428, but only (normally) bored to 4.05- which would of course be a cost savings over casting different blocks for service use when not necessary. Actually makes perfect fiscal sense, and would explain some 360s and 390s with "thick" walls

bingo, dead on the money. Every single one I have seen so far is a mid seventies block. My guess is, theres a lot more out there to be found, I would be willing to bet there were probably at least 500 or so cast its a simple question of economy of scale. Ford didn't do 5 or 6 blocks at a time for bread and butter stuff, they did hundreds at a time. By casting them all on 428 cores, they didn't need to cast, and warehouse two runs of blocks, one for 360/390s, and one for 428s, they could cover both replacements with the same block, and machine them to the bore size they needed.
Of course, when you think about how many MILLIONS of 390 blocks were cast over the years, they are going to constitute probably less than 1% of the total number of 390s out there, (which is right in line with Barrys quoted numbers) and probably quite a few thick (and thin) blocks are Toyota corollas by now, so you are going to have to look at a HELL of a lot of 390s to find one. If you are looking for one, once you realize they are all late blocks with the vertical ribs, you can eliminate a lot of them without even popping a freeze plug. Theres still a damn site more thick 390 service blocks out there than there are OEM 427 cammers, and if I went on an internet forum and said those "didn't exist" the same guys that are saying "all 390s are thinwall" would go spastic. But blabbing about cammers is "cool", talking about thickwall 390s clearly is not.
FWIW, my block came to me indirectly via another one of those "old-school" Ford guys like Gene is talking about, he was pretty well known locally, there is  at least one member silently lurking this thread who knows exactly who I'm talking about, he also had two shotgun mustangs, one pretty much stock, the other with a raised port, dual dominator Pro-Stock motor in it, the second one was pretty notorious among local street racers in the early seventies. Lots of those guys knew about these blocks back in the seventies when they were new, hell I knew about them, and I didn't have any kind of inside track, I was a punk kid at that time.
Its a fair bet that a fair percentage of that 500 or so have been hoarded by the few guys that knew what they were, and there are probably a few out there like mine, that have been sitting in a dry basement for 20-30 years. A lot of those guys are older than me, (and I aint exactly young) and are probably closing in on the time when they are going to stop hoarding this stuff. But hell, they "don't exist" so you guys here don't need to worry about that.

[fryedaddy]

first of all im going to clarify im not a engine builder or machinist.i used to buy a new ford performance magazine every month from 1980-90ish.i read in a article-cant remember which mag or when, that made a statement that the 66 7 litre gal had the best all around fe blocks.it said they had thicker walls than most.im not claiming this to be true because i brought this up 4 or5 years ago and i got shot down like a criminal.i just thought i would bring this up because of this tread,so please dont shoot me down again .you guys convinced me the first time that this is not true.i wish i could find the article.the author of the story had what looked like hundreds of blocks lined up on the floor of a warehouse.thats why i brought it up in the first place.i thought it might be legit.

[MeanGene]

I remember what our local, quite sharp dealership parts guy told us in the mid-70's, that if you bought a 428 service block then, you would get a bored out 391 block, as they were using one service casting based on the 428, but only (normally) bored to 4.05- which would of course be a cost savings over casting different blocks for service use when not necessary. Actually makes perfect fiscal sense, and would explain some 360s and 390s with "thick" walls

bingo, dead on the money. Every single one I have seen so far is a mid seventies block. My guess is, theres a lot more out there to be found, I would be willing to bet there were probably at least 500 or so cast its a simple question of economy of scale. Ford didn't do 5 or 6 blocks at a time for bread and butter stuff, they did hundreds at a time. By casting them all on 428 cores, they didn't need to cast, and warehouse two runs of blocks, one for 360/390s, and one for 428s, they could cover both replacements with the same block, and machine them to the bore size they needed.
Of course, when you think about how many MILLIONS of 390 blocks were cast over the years, they are going to constitute probably less than 1% of the total number of 390s out there, (which is right in line with Barrys quoted numbers) and probably quite a few thick (and thin) blocks are Toyota corollas by now, so you are going to have to look at a HELL of a lot of 390s to find one. If you are looking for one, once you realize they are all late blocks with the vertical ribs, you can eliminate a lot of them without even popping a freeze plug. Theres still a damn site more thick 390 service blocks out there than there are OEM 427 cammers, and if I went on an internet forum and said those "didn't exist" the same guys that are saying "all 390s are thinwall" would go spastic. But blabbing about cammers is "cool", talking about thickwall 390s clearly is not.
FWIW, my block came to me indirectly via another one of those "old-school" Ford guys like Gene is talking about, he was pretty well known locally, there is  at least one member silently lurking this thread who knows exactly who I'm talking about, he also had two shotgun mustangs, one pretty much stock, the other with a raised port, dual dominator Pro-Stock motor in it, the second one was pretty notorious among local street racers in the early seventies. Lots of those guys knew about these blocks back in the seventies when they were new, hell I knew about them, and I didn't have any kind of inside track, I was a punk kid at that time.
Its a fair bet that a fair percentage of that 500 or so have been hoarded by the few guys that knew what they were, and there are probably a few out there like mine, that have been sitting in a dry basement for 20-30 years. A lot of those guys are older than me, (and I aint exactly young) and are probably closing in on the time when they are going to stop hoarding this stuff. But hell, they "don't exist" so you guys here don't need to worry about that.

Yeah, but the difference is I just posted a little knowledge from doing this a very long time, without writing a supersecret novel or doing "mocking" drama. This a is not a deep dark secret that only you and your ego know, we actually bought a couple over the counter back then, and the parts man put one in his '76 Highboy. And has very little to do with the scores of regular 390s and 360s built over the years that will not safely go 4.13, despite what Billy Joe Jim Bob's second cousin Darryl's uncle says

[thatdarncat]

It’s not that many of us don’t know about the thick walled factory blocks that exist, but as was pointed out early in the thread, that’s NOT the question that was asked, so there’s no need to snicker. I’ll even share my experience on them - all the thick walled somewhat common blocks I’ve seen have been 361/391 FT ( not FE ) blocks. They have all been “DIF” ( Dearborn Iron Foundry ) cast blocks, and they have all had the common 428 block identifiers - a scratch mark on the rear of the blocks ( multiple types ), a “428” cast somewhere in the bottom of the water jacket, and the specific 428 water passages on the deck that DIF blocks had and are called out on the blueprints. This is the type of block Jay has, and I have one too, and I’ve seen actual pictures of many more. My guess is thousands were cast. All the blocks I’ve personally seen had date codes between about 1970 through 1972. I have seen reports of some of these blocks with date codes down to about 1968. It’s possible they went all the way until the end of DIF production. I personally have checked many 361/391 FT blocks looking for these, and my experience has been that not all the FT’s at this time had the 428 cylinder cores, including some FT blocks I checked all the way to 1966 date codes, so I don’t think it’s a sure thing, but they’re out there if you focus your search in this area. And the more verified info people share, including date codes, casting plants, and sonic tests, the better. I have also seen reports and sometimes actual pictures of the rare occasional regular 390, 406, ext. block with unusually thick cylinder walls, so those unicorns exist.


However, that wasn’t the question originally asked, and why most of us weren’t focusing our answers there, not because we didn’t know this or believe this. The question originally asked was whether early FE blocks were cast with “thick” walls and then there was a switch at some point to “thin wall” blocks, there is no evidence that happened.

And my experience with everyone who’s opinion I trust is the same, leave the cylinder walls as thick as possible for best ring seal.

[Sand hauler]

It’s not that many of us don’t know about the thick walled factory blocks that exist, but as was pointed out early in the thread, that’s NOT the question that was asked, so there’s no need to snicker. I’ll even share my experience on them - all the thick walled somewhat common blocks I’ve seen have been 361/391 FT ( not FE ) blocks. They have all been “DIF” ( Dearborn Iron Foundry ) cast blocks, and they have all had the common 428 block identifiers - a scratch mark on the rear of the blocks ( multiple types ), a “428” cast somewhere in the bottom of the water jacket, and the specific 428 water passages on the deck that DIF blocks had and are called out on the blueprints. This is the type of block Jay has, and I have one too, and I’ve seen actual pictures of many more. My guess is thousands were cast. All the blocks I’ve personally seen had date codes between about 1970 through 1972. I have seen reports of some of these blocks with date codes down to about 1968. I personally have checked many 361/391 FT blocks looking for these, and my experience has been that not all the FT’s at this time had the 428 cylinder cores, including some FT blocks I checked all the way to 1966 date codes, so I don’t think it’s a sure thing, but they’re out there if you focus your search in this area. And the more verified info people share, including date codes, casting plants, and sonic tests, the better. I have also seen reports and sometimes actual pictures of the rare occasional regular 390, 406, ext. block with unusually thick cylinder walls, so those unicorns exist.


However, that wasn’t the question originally asked, and why most of us weren’t focusing our answers there, not because we didn’t know this or believe this. The question originally asked was whether early FE blocks were cast with “thick” walls and then there was a switch at some point to “thin wall” blocks, there is no evidence that happened.

And my experience with everyone who’s opinion I trust is the same, leave the cylinder walls as thick as possible for best ring seal.

Exactly, I got one of those to,lol

[67xr7cat]

I've been hearing the same stories all my life... this block is a thick wall casting, this block is high nickel, this block is a special high performance only came in GT40's and dump trucks....

I've seen a lot of sonic sheets for FE's and 385 series over the years and they go all over the map.  Rare is the block that can go .080" in all eight holes without thin spots, rare is the block that is too thin to go .030" too. What you have to realize is these are castings cast in the 1,000's of units. If you look back at what Ford was doing the move towards "thin wall" casting started in the early 50's.  Everyone thinks was all about using less cast iron, which of course was a goal, but you have to look at what was going on with the engine designs. The bore spacing was getting smaller and the bores getting bigger ( (relative to each other) leaving less room for the core. Thinner cores break easier and result in more scrap. If you can thin downs the walls you can maintain the needed core thickness. If you read some of the old SAE papers the industry as a whole was looking to build more compact engines, use less cast iron, and at the same time reduce scrap. When you cast blocks you always have blocks that get scrapped and blocks that have to be repaired. This is a huge deal and lowing that number was way more important than saving a few pounds in the casting process.

Bottom line in any block cast as a 390 meaning with 390 cores some will be thicker than other, but most will fall in the middle of the range. Is about what I've seen over the years and makes sense from a manufacturing point, especially when you take into account what was going on by the early 50's.

If you find a block with 428 cores that is a 390 then it is a 428, just like a 406 is a 406, and a 427 has a 427 core (which can vary by years...). If you have a 352 or 390 cast with the stand core and think can be bored out to a 427 by all means do. your block, your money, your time.  If it fails on your, well it is your wasted time, and wasted money. If it don't guess you got lucky. Is called gambling.

My suggestion is if you want a 428 block you need to find a block that has 428 cores meaning a 428 block, if you want a 427 you find a 427. Finally keep in mind all this stuff is 40 - 60 years old and just finding a good core that don't leak or have a crack can be hard enough.

[My427stang]

Agree with Brent 100%, periodically I find a decent 390, but I also had 2 that were real thin at .030.  I can't imagine a .125 cut, unless you find a real good block.

Make the bore straight, spend the dough on heads, intake and headers, if you want more displacement, add stroke

Falcongeorge, you get so wound up you miss what people say.  I have had 2 motor mount bolt blocks that can handle boring, not too many 4 bolt motor mount later versions, but take a breath, build whatever you want the way you want it.  Of course there are some, nobody debated that for a bit,

You don't have to agree with me, but I don't have to agree with you either.  Of course I have seen some thick ones, but your drill bit test doesn't guarantee it, no matter how much you get fired up, these blocks were not built precise, side to side they aren't even the same, even if the drill bit test checks good. 

Don't check 'em, check 'em, I don't care what you do, but once you get playing with a sonic tester, you'll be trying to figure out "how thin is too thin?" on the majority of 390s and industrial 428s, because that's what you will find. 

[plovett]

I know all of you are tired of this debate...….. But I want to clarify one thing.  Even if you find a 390 that can be bored 0.080" over and still have acceptable cylinder wall thickness for the intended use, it is still a thin wall casting, in my opinion.

It is just slightly less "thin".   

It is kind of like arguing philosophy.  It almost always eventually degrades into an argument about definitions.  What is "thin" and what is "thick"?

JMO,

paulie

[FERoadster]

I've been holding back this comment for days,  but did the "Ideal FE blue Prints" call for a block with thickness to be bored to 4.13 ??
Then manufacturing/casting tolerances would have been OK if there was no casting shift in the ideal world. Remember life will kick you in the A$$ and things get off kilter.
So in the perfect world with no casting shift could the as designed FE 390 blocks be bored to 4.13? Pre or post 1965? the date of 2 to 4 bolt motor mount pattern.
Inquiring minds.

Richard >>> FERoadster

[67xr7cat]

I know some on the other forum have some of the factory drawings so if they see this thread maybe they will chime in. I doubt Ford cared if a block could be over bored more than .030" which is the typical overbore for a rebuild, JMO.  Really, Ford is a manufacture casting blocks, making cars, trying to make a profit. If it made it out the door and out of warranty I doubt the foundry cared about if someone 30 years later can bore it .080" over.

My question has always been what is a safe wall thinkness? I'd say this number varies by use and everyone I ever asked had a different opinion on it. I can say you get under .080" on a non thrust and not likely to survive. .100" seems ok, .120" better... 

[jayb]

Hopefully all the enmity has gone out of this discussion, I'd hate to lock the thread because it has been an interesting topic.  For what it's worth, my personal limits for wall thickness are 0.125" minimum on major and minor thrust surfaces, and 0.100" on front and back.  The further down the bore the thin spots are, the more comfortable I am with the block.  And 427 blocks are different because the cross section of the bore looks like a cloverleaf, rather than a round cylinder.  My opinion is that on a non-thrust surface, you can go even thinner on a 427 block than 0.100", and in fact the 492" dyno mule I tested in my book was 0.060" over 427 block with the thinnest spot around 0.080".  That engine handled some pretty abusive dyno testing, up to 675 HP and 7000 RPM with 20+ different intake manifolds, and has never given up. 

And let's not forget the tune.  If you are on the edge of detonation you are much more likely to hurt the block than if you are running safe with good fuel and timing.  I personally think a manual trans is harder on a block than an automatic, especially on a car with slicks that's dumping the clutch at high engine speeds.  Higher horsepower will also stress a block more, obviously, with greater cylinder pressures.  Lots of factors at play here...

[FERoadster]

Yes I've got Shoe's prints but they are copies of the 427 only prints and involve 30 or so different sections to see an entire block.
I'm sending them to Lance Hargis (428Kidd) as a moderator on the FEForum since I only got them for safekeeping since I've got lots of space in my Library for things like that.

Richard

[winr1]

I had a D3 service block that the space between the cylinders looked tiny

It weighed 5 or so more pounds than my other 15 or so 390 blocks weighed
.........

Had 5 other 390 and 391 blocks that were heavier than my 352 blocks

Seems with larger bore would weigh less ??



Ricky.