347 build for my 64.5 mustang

[Joey120373]

In my book the 530 HP in a stock 5.0 block is not the big problem.  It's spinning a stroker rotating assembly to 7,000 rpm in a stock block.  At those speeds the "inertia load" from the piston/ rod assy on the main bearings vastly exceeds the "combustion load" that makes the horsepower.

If it was me I'd get the aftermarket block for plenty of revs without puckers.

Thanks for the input, and I agree, I have always thought that RPM is harder on a motor then how hard the piston happens to be pushing down on the rod.

I also think that a lot of the blocks that are splitting are being used in drag race cars. I think it’s also one of those deals where, if the engine just works, nobody notices it, but when the block splits in two, well then everybody notices it.

I guess I should have pointed this out in my first post, but I know full well I’m flipping a coin using a factory block. No shortage of people who have cracked a block, yet there are also lots of people who run and rev the snot out of a stock block for years and no issues.

Part of the reason I went big on the heads and valve-train is a bit of pre planning if the block does fail .If that happens, or even if it doesn’t and I just wanna play with it, I can take all those parts that are overkill on a 347 and swap them over to a 363 where they aren’t so overkill anymore.

[Joey120373]

Please help me with my perpetual ignorance.

Why not install a 351W instead of a 302 stroker.

If the answer is that the engine is slightly wider and you don't want to "notch" anything for the install into your 64.5...that's silly.

Anything near an actual 500hp motor is going to twist that 1965 Mustang like the proverbial pretzel. I'm ass-u-me there's going to be subframe connectors, a 9" install with all the goodies to hook 500hp and so on.

Sooo...I say cut away...and make that a 393 or 408W stroker.

Tommy, your my kinda guy! I have thought about a 351 block a lot, and every time I do, I end up at a 427 or 460 stroker in an aftermarket block, the biggest heads and “Katy bar the doors” .
To me it seems really silly to spend $3000 on an aftermarket 302 block, when the 351 version essentially costs the same and offers another 100 cubes .

But I want to keep it a small engine, I want it to look “right” in the engine bay.

Making 500 hp with a factory 351 based 408 stroker is pretty easy and cheap, and would last forever.
That is the smart way to do it, but I want light weight and high revs. Longevity is not a concern for me.

[Joey120373]

While the 351W block, is stronger, I've always liked the 8.206 deck. If you don't already have the block, I'd stay away from the HO blocks and go with the earliest 302 block, that you can find. The blocks I use are C8, C9 & D4, they are stronger. The jury is out on how much strength a girdle adds but, they are cheap and I would add one.

I’ve already got the block, and I was going to ask about the girdle. I kinda feel the same way, a girdle may not help, but unless it could hurt in some way, I don’t see a down side to having it.

[Joe-JDC]

If you do add a girdle to the mains, make sure it is steel, not aluminum.  Around here the ONLY failures of the blocks were with the aluminum girdles that were supposed to absorb vibrations, but actually grew with the heat and helped split the blocks.  I put a 351W in my 1966 Mustang back in 1972 with 4 speed, and that was one of the best driving cars I have owned.  Plenty of torque, light weight, and would run with the big block crowd all day with ease.  I put a 351W in one of my '66 Fairlanes with 4 speed also, and that was a great daily driver.  Raced a 351W in my '69 Mach I for several years before going to 427, and have a 383W in my '86GT now.  I have a 427 Dart Windsor ready, a 410W ready, and if you ask me what my favorite engine is after all this, then you weren't paying attention.  Joe-JDC

[blykins]

If you do add a girdle to the mains, make sure it is steel, not aluminum.  Around here the ONLY failures of the blocks were with the aluminum girdles that were supposed to absorb vibrations, but actually grew with the heat and helped split the blocks. 

That's why I say girdles don't do anything.  The 347 that I have mentioned several times in this thread has a DSS aluminum girdle on it.  When I first built the engine, the owner brought the block in with the girdle on it, so I just used it.   It's had 100's and 100's of passes on it. 

I think it's up to the block on whether or not it's going to take a dump.   Just the luck of the draw and a girdle (or lack of) isn't going to change things.

[fekbmax]

My block and rotating assembly have been at the machine shop since last june, and it hasn't yet been touched.


Joe

WoW, 10 months in the machine shop and hasn't been touched ? You got way more patience than me.  I thought 6 weeks was to long to leave stuff just setting. 

[Joey120373]

My block and rotating assembly have been at the machine shop since last june, and it hasn't yet been touched.


Joe

Not casting a bad light on the machine shop, I told him when I dropped it off that I was NOT in a hurry for the motor, as I had a feeling it was going to be a while before I had the heads in hand. So while I was hoping to see some progress after 10 months, I can’t hold it against him. When I checked in a few weeks ago, he said he was waiting for a weekend where he had nothing else going on and no distractions, I am hoping that is the case.
WoW, 10 months in the machine shop and hasn't been touched ? You got way more patience than me.  I thought 6 weeks was to long to leave stuff just setting.

[Joey120373]

Brent, I am following your new dyno mule build, I do t know how fast you intent to spin that sucker, but the aluminum rods and JE rockers lead me to believe you will be spinning it up there a bit.
I’m guessing you will be using every bit of flow those 180cc heads have to offer.

I may hit you up for a roller cam and lifters for the 347. And I might talk to Joe about working on an intake for me as well.

[blykins]

Brent, I am following your new dyno mule build, I do t know how fast you intent to spin that sucker, but the aluminum rods and JE rockers lead me to believe you will be spinning it up there a bit.
I’m guessing you will be using every bit of flow those 180cc heads have to offer.

I may hit you up for a roller cam and lifters for the 347. And I might talk to Joe about working on an intake for me as well.

I'm trying some new lobes that I've never tried before, so I'm not 100% convinced on how high it will turn, but the goal is pretty high...

I've done a poop load of SBF/AFR head combos.  I can help on the camshaft for sure.   

[Rory428]

@pbf777

“     Just don't cry when it breaks! ”

Won’t cry a bit as long as the heads are ok 

On my list of criteria, a 200,000 mile motor is way, way down on the list. If the block breaks, just gives me an excuse to step up to a good block.

Unfortunately, if the block breaks, there is a real possibility that your reciprocating assembly, as well as the heads, won`t "be OK".

[machoneman]

I agree with Rory as if the block splits, it's worse than 50/50 that the heads will take a hit. Agree with Brent on the DSS alum. girdle as I well knew the owners from long ago and had my block work done by them. DSS has sold a ton of those girdles btw.

Still, I never used one in my 351s as I didn't think it was helpful AND early vintage 351W's like mine rarely had main saddles let go. Later 302W's (5.0's) with thinner metal often did have saddle cracks and owners may have found any girdle somewhat helpful but I still doubt their effectiveness over time with hard running of these blocks. 

[pbf777]

Unfortunately, if the block breaks, there is a real possibility that your reciprocating assembly, as well as the heads, won`t "be OK".

     I would not dispute this statement; but generally in the instances of the block splitting in half thru the valley, one has notice prior to the catastrophic separation as generally the cracking begins in the main saddle(s) area, propagates upward into the camshaft tunnel bulkhead, and at that point often the cam bearing retention crush is lost, the bearing shuffles out of position and/or spins and there is a notable loss in oil pressure!   

     Of course that is if anyone is paying attention!    But partly this blame can be at times be laid at the feet of the O.E., as the oil pressure "gauge" mounted in the dash of a Fox Mustang will read "NORMAL" until the oil pressure drops below the switching threshold of something like 5 P.S.I.!   

     Scott.

[Joey120373]

Ok, after thinking on it for a few weeks and taking in all the comments, here is where I am leaning today......

Stock roller block bored .030 and a 347 stroker kit, Scat crank ( forged or cast, probably forged ) Scat I beam rods, Mahle flat top pistons ( 4032 alloy ) .
AFR 185 or 195cc heads, still waffling on that, I know the 185s are plenty good enough. But I don't think the 195s would be " too big", and the added headroom might come in handy down the road.
 Shooting for 11-1 CR. ( I live at 4500 feet )
Hydraulic Roller cam that peaks power in the 6300-6500 range.
May still do the Jesel shaft mount rockers, mainly because I want to use stock type valve covers, I want the engine to look relatively " stock " .

This combo should easily put me in the ~ 450/450 (tq/hp) range I suspect, depending on what intake I use. 

Brent, I will take you up on the cam offer, I will be in touch.

[Falcon67]

>I think it's up to the block on whether or not it's going to take a dump.

This. Same with an 8" rear - they'll do X until they won't.  Put nearly 1K passes on an 8" until it ate its self.  Replaced with 9" 31 spline parts - no more problems in 20 years.

I've seen stock 302 blocks go year, two in a "small tire" type car with hella spray before they failed.  And I've seen a N/A 347 make 4 passes at low 7s 1/8 mile and fall apart.

I've split many cylinders in 351C blocks.  Won't buy or machine another unless it's for a putt-putt show car.  My spare 302 makes about 300 and is shifted at 5800, no more.  My last stock block 351C makes about 480, limited to 6200.  The new 427 motor - Dart.  Not going to blow $1500+ on machine work for a stock block that may last 20 years or 20 minutes.

[Joey120373]

I keep going back and forth on the aftermarket block issue. I don’t know what the actual weight penalty is on the block, I’ve heard about 60 pounds ? Has anyone actually weighed the two? I have a stock block I could weigh.