Boredom 391FT thoughts

[My427stang]

Ross, you just do not know that. It's just your opinion and speculation. Only hands on testing of pre '72, 361 - 391 will prove it, or not but, it's something that could be beneficial for FE builders. Core shift is random and may or may not be present in any block.

Frank, I do have direct knowledge, you don't. I just lumped it in a wide range of blocks for one constant, lack of consistency. 

As far as helping builders, do it, measure some.  I can say I do. I have an A-scratch I just completed and a std bore 68 390 behind it....4th drawer down on the right side of my engine-specific tool box sits a sonic tester.

My experience has shown me exactly what you are saying, "core shift is random"  How do you think you check for it, call TRW?  A sonic check, which is what we have consistently said, is only way to check it.

Quote me with your reply to remind me that this will be my last word because I have wasted the forum's time and let you get under my skin again

[cjshaker]

20 years of the FE forums, thousands of users that include pro racers and guys that have raced FE's from the early days to present (some of them gone now, from age), hundreds and hundreds of posts about block thicknesses of all the different FE blocks, and the vast consensus is that all blocks should be sonic checked at anything other than the smallest overbore. But Frank will believe what he wants to believe.

[frnkeore]

When did I say that sonic testing was not useful? Show me the post.

Regarding truck cranks, the crank snout is much larger and has to be machined to work with car accessory's. The timing cover, is also way different and cast in iron.

Go for it, YOU do it, YOU see, YOU take the chance and report back. TRW catalogs are not an accurate source of block thickness. Sonic testers are cheap and so are 391 blocks. I would love to hear back your findings

Ok, direct me to the first 10 or 12, 361/391 blocks, please. I'll take a look at them tomorrow. It would also be nice to see the log book that you've accumulated on sonic testing of the truck blocks. I used to have mine but, I lost it just before coming on this forum

I'm a machinist of at least 47 years, for TRW to waist the ink that they put in that statement, I think they would have had to have know about a Ford revision. Are you guys saying that TRW, were intentionally misleading the automotive industry?

Again, I didn't post that info, to be attacked. I thought it was interesting and that it might be helpful. I didn't even say it was a fact, just that I found it in a TRW catalog!!!

[RustyCrankshaft]

While I'm at it, I will ask everyone on the forum.......... Has anyone either, allen wrench or sonic tested any pre '72 361 or 391, truck blocks?

Yes I have. I used to own several 391 and 534 powered Ford medium duty trucks (and still have a couple). I have 2 cabovers with 391's, a 69 and 70, both were purchased from the original company with complete service history. They were pretty tired when I got them and had to rebuild both shortly after I bought them. 1 block was definitely thicker and would go 80 over easily. The other one had enough core shift one bank would have been down to about .060-.070 at 30 over and I ended up having to replace that block. Might have been fine in a pickup or car, but I wasn't going to trust it running full throttle at 41k lbs 4k rpm hours at a time (at whopping 18mph heading up the hill to the landing). I don't remember if it was the 69 or 70 truck that had the bad block, both were pre 72 engines that were original to the trucks.

[cjshaker]

I'm a machinist of at least 47 years, for TRW to waist the ink that they put in that statement, I think they would have had to have know about a Ford revision. Are you guys saying that TRW, were intentionally misleading the automotive industry?

What they're saying is that, nearly 100% of the time, parts manufacturers get it wrong when posting general info about stuff. They're interested in selling products, nothing more. When you read a cam card, do you take the "cam characteristics" at face value? Because they're stated as if it were fact. But we all know a big stroker 480+ cube engine is going to act vastly different than a stock stroke 390, with the same cam. Manufacturers, and the internet in general, are full of wrong, misguided and generally stupid information. You can go to nearly every website or forum that doesn't cater to FE's, and when the subject comes up on a project about FE's, you will see bad information given as gospel. Only here, or the other forum, will you get good solid information that you can rely on and trust. But that's only if you actually listen.

[TomP]

I never chuck anything away so maybe I've still got the paper thin 361 block under the bench. That was bought because I expected it to be a thickwall block. It fit a larger drill bit than my 332 did. Bigger than 3/16".

[chris401]

In 1965 when the FE went into pickups the stock 352 got the 390 cores. In most cases those are good for a 4.11" bore and likely the cores were straighter than the latter standard webbed blocks. Maybe that fact turned into the argued point above? I can see how someone could take part truth and print a marketing magnet.

Around 1971/2 my dad bought a 63 drag wagon with one of those .120" overbore 390's. One night a couple of the "paper thin" cylinder walls collapsed. He didn't believe anymore 390 to 428 builds.


It has been a while back so if you remember the post feel free to tag it here.

I had a D3TE block that was a 4.080" bore. Although 6 or 7 cylinders were good for a 4.16" bore seems it was #3 that was at .095" wall. Maybe that was the only thin cylinder. It's been a while.

EDIT: it was .030" over 428 NOT 4.19"

[chris401]

I have a 390 that I got from Blair that was originally intended for a fun heavy street car, and I use it in my '70 F350 dually to pull 9k+ lbs through some hills in Pennsylvania and Ohio. It's about 9.5 compression, C4 heads, Edel RPM intake, Holley 750 with an unknown spec cam that has a nice little rumble to it. I kept the performance timing curve that Faron put in it, used an MSD Blaster ignition to fire it, and with 93 octane it pulls fine with no hint of detonation. That's with the NP 435 and 4.11 gears with 29" tires. I DO keep the RPMs up though, and never lug it in anything but 1st gear. I'd never have to drop to first, and I'm confident that it would pull fine in 3rd up about any hill that I'd encounter in it. I've actually never had to drop a gear to get up a hill yet, although from a takeoff I've held it for all she's worth before going into 4th. I do wish there was an easy 5 spd to bolt into it, but it is what it is for now.

The 390 doesn't have any issues pulling up the hills, but I've still got a 445 that I'm about to drop in it. I went that route for the extra torque. It'll use the same type C4 heads and RPM intake, and about the same compression. Maybe a bit less at around 9.3. As long as I use good fuel and don't lug it, I don't expect any issues pulling with it either.

I just posted this to show that it is possible to tow with a stock type drivetrain. When pulling heavy loads with a gas engine, I think RPMs are your friend, to keep the engine load lighter and away from detonation. As long as the engine is built good, a good tune, timing and an eye on plugs is key to make sure you're in the safe zone.

Careful Doug. Do you have the frail 16 spline Dana? With that undrivable drivetrain your just a couple of rpms away from my gas rig with a cork intake and a carburetor that only looks good on paper.

[blykins]

When did I say that sonic testing was not useful? Show me the post.

Regarding truck cranks, the crank snout is much larger and has to be machined to work with car accessory's. The timing cover, is also way different and cast in iron.

Go for it, YOU do it, YOU see, YOU take the chance and report back. TRW catalogs are not an accurate source of block thickness. Sonic testers are cheap and so are 391 blocks. I would love to hear back your findings

Ok, direct me to the first 10 or 12, 361/391 blocks, please. I'll take a look at them tomorrow. It would also be nice to see the log book that you've accumulated on sonic testing of the truck blocks. I used to have mine but, I lost it just before coming on this forum

I'm a machinist of at least 47 years, for TRW to waist the ink that they put in that statement, I think they would have had to have know about a Ford revision. Are you guys saying that TRW, were intentionally misleading the automotive industry?

Again, I didn't post that info, to be attacked. I thought it was interesting and that it might be helpful. I didn't even say it was a fact, just that I found it in a TRW catalog!!!

TRW obviously had some wrong information.

[64PI]

I'm currently putting together an early 391 block that is .080 over and half filled. The drivers side bank on the valley side cylinders all check out at .170"-.180" thick. Outside of the cylinders are all around .120"-125". The passenger side has minimal shift and all cylinders check out around .140"- .150".. I'm glad I half filled the block after seeing the shift on the drivers bank. A drill bit test isn't going to tell you whats happening on the thrust sides of a cylinder.

Fred

[cjshaker]

Careful Doug. Do you have the frail 16 spline Dana? With that undrivable drivetrain your just a couple of rpms away from my gas rig with a cork intake and a carburetor that only looks good on paper.

Chris, I couldn't even tell you what a 16 spline Dana is..lol  I assume the axle spline count? I never bothered to count the splines whenever I've replace bearings and seals in them, but I know the axles are big, and heavy! I've hauled 5000 lbs in the bed of my old '68 Highboy with a Dana 60, and it never had an issue with it (except for nearly killing the tires and ripping my bed apart in the process ), so I figured the Dana 70 would be fine with any loads I'd put on this truck. This is my 4th truck with a Dana rear, and I've never had to do more than replace some leaking seals and a few bearings on them...ever, so I couldn't tell you much about them, except they seem pretty much bullet proof. All I did on this truck was replace all the bearings and seals and put in a heavy synthetic gear oil, and called it good.

With such a heavy load, I was slightly concerned about braking, but that has turned into a non-issue. I have the trailer brakes set a bit on the heavy side, so they initially pull on the truck when first activated. After the initial hit of the controller, and the subsequent rolling back, I can barely even tell the trailer is back there. Trailer brakes are cheap enough and easy to replace though.

The only difference I see in my junk and new junk is.....they have better creature comforts, and they get better gas mileage unloaded. Once loaded, that equals out pretty darned quick! Oh, and I don't have (and can't afford), a $500-$600 truck payment..lol

[TJ]

From my research, the 16 spline (and 30 spline) break while rock crawling with it in 4 wheel low, granny 1st, and a hard locker in the rear.  I think you’ll be fine if you behave.   Every once in a while I have the idea to switch to the chrome moly axles and the claimed stronger ring and pinion but haven’t yet.  I have an open differential and don’t mash the gas in low gears.

My truck is a ‘65F250, btw.  Towed 5 ton many times outta state.  Was a 390 for a while. Now it’s a 482.

[jayb]

Since this is not Facebook, name calling and sarcastic remarks are not required.  I have edited and/or deleted some of the posts in this thread as a result of commentary not appropriate to this forum.  Please keep a civil tone, guys...

[Gaugster]

Well - I can't add much to this thread other then a public service announcement. You really need to know the health of the block and what you are getting into. Sonic testing is cheap insurance. There are plenty of examples of Ford trucks purchased for a few hundred bucks and dragged out of a field that yield a "$4000 428 CJ blocks". I am not saying that anyone here has ever done that but the market for FT/FE blocks is tricky to say the least.

[frnkeore]

In doing a little research, last night, I found is, citing a FordFE.com post:

This one test is the single best way to quickly identify an assembled FE block, and credit for it goes to FordFE.com forum member David “Shoe” Schouweiler. You only need the simplest of measuring tools– some drill bits.

Remove the center freeze plug from the side of the engine block. Using common drill bits, then slip the shank portion of the largest possible bit in between the center cylinder cores through the freeze plug opening. The size of this largest drill bit indicates which water-jacket core was used to cast the block.

If you can only fit a 1/8- or 9/64- inch drill bit shank between the cylinders at the largest gap position on the block, and a 10/64-inch bit doesn’t fit anywhere, then they are 427 water jackets.

406/428/DIF361/DIF391 blocks allow a 13/64-inch drill bit shank to fit into the gap at the largest position.

MCC361FT/MCC391FT blocks (MCC = “mirror 105” marking) allow a 14/64-inch bit to fit between the cores.

Regular 360/390/410 blocks hang around the 17/64- to 19/64-inch water-jacket space at the largest position on the block.

These are only approximations, but tend to be close.

I've included the TRW warning. It applied to 359, 361, 389 & 391, truck engines. There are no warnings of this nature, for any car engines. By that, I'm not saying car engines were thick wall, just that TRW had a reason to relate is info for FT engines, only.