1. 1slowfox90

    1slowfox90 Member

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    Some of you have probably seen my first post about build ideas for my fox.
    So far my goal is 500+hp and preferably keeping it a manual trans.

    I just got an offer on a 74 351w block with crank, rods, and pistons. Needs rebuild but hes asking only $150.

    Do you guys think this block is going to hold up? Like i said before i would like to make 500hp easy and a few of the guys i talked to said this block should be fine for that. I highly doubt i am going to use the stock internals anyway, i might get a stroker kit for a 393 or 408 or something.
     
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  2. revhead347

    revhead347 I have face herpes.

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    Those blocks are strong. The problem is miles. If the engine has already been revved up a lot in a street car then it has started to get metal fatigue. If it's been in an old truck that doesn't rev up much, then you are good. The expensive part of those engines is getting good quality roller lifters in them. If you are ok with flat tappet lifters then it's cheap. Just a hassle to add zink to the oil each time.

    Kurt
     
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  3. NIKwoaC

    NIKwoaC 中國製造

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    Windsor blocks are supposed to support 700+ when built right, with the early blocks being arguably stronger. Like @revhead347 said, the trick is in converting to roller cam (not exactly "tricky", but it will cost you a few hundred bucks), plus the rear main seal will be 2 piece.

    Google it, there are a bajillion threads on 351 blocks. IMO, Ford built the 351 the way that 302s should have always been- bigger fasteners, blind main bolt holes, etc.
     
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  4. revhead347

    revhead347 I have face herpes.

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    The 351 blocks are a little stronger than the 302 blocks, but not much. The big advantage is that there is enough metal in the bottom to drill it for 4 bolt caps. 4 bolt caps walk a lot less which prevents the fatigue issues that lead to cracks in Windsor style blocks. With stock 2 bolt caps they really aren't much better than the 302 blocks.

    Don't get tied up in all the supposed hard hp figures each block can handle. What causes a block to crack has a lot more to do with how it makes power than how much it makes. 700hp out of 351 block is not atypical, but then again there are guys making 900 to the wheels with stock 302 blocks with big turbos and less rpm. RPM is the real killer. The higher and more frequently you rev it, the faster it will crack.

    I also wouldn't judge Ford for how they built each block. A 351 Windsor engine is not a performance engine like most people believe. It's a big heavy block that's got a lot more metal in it because it was designed to be a truck engine. It's designed to be a higher load more frequently. The 302 was also used in cars, and needed to be lighter for performance. The way they should have built a performance engine was to deep skirt it like their European counterparts were doing at the time. All modern performance V8s have deep skirts, where as the block rigidity in a Windsor style engine ends at the crank centerline. The larger performance engine of the time from Ford were the FE style blocks.

    Kurt
     
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    Last edited: Jan 5, 2014
  5. NIKwoaC

    NIKwoaC 中國製造

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    Eh. 302 blocks, particularly the late roller blocks, are a gamble above 400 HP, and on borrowed time above 500. On the other hand, 500 HP with a main-studded 351 is considered mild, with a lot of guys doing 600+ without a second thought. Like any factory block, there are always large variations, but the 351 seems to be an honest-to-goodness 2-300 HP more stout than the 302.

    The early W had enough meat for the conversion, but the later ones do not. Main studs with the proper lube and torque seem to limit cap walk enough for the late Ws to survive though. 351s have more meat, blind holes, bigger fasteners and bigger, thicker caps than the 302. The 302 with its smaller thru holes and paper thin mains just lack the reinforcement to reliably last under elevated power levels.

    I agree, HOW you make the power has a lot to do with block survival, and RPM is hard on parts in general. You need to show me an example of these 900 HP stock 302 blocks though- that's a bold claim even for a Mexican or a B50!

    Really, what probably should have happened, is they should have continued offering a 4-bolt version in the Windsor family like the early Boss 302 blocks. I could never quite wrap my brain around why they had the 4-bolt 351C, and then the 351/400M had (unused) provisions cast into the block for 4 bolt mains, and they even had engineering history with a 4-bolt 302, but they failed to ever offer a production 4-bolt 302 (or 351W) beyond the Boss cars.

    People argue that cost was a factor, but the modular motors have probably twice the fasteners in them as the SBF.

    Eh, now I'm just rambling.
     
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  6. revhead347

    revhead347 I have face herpes.

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    I have seen a limited number of stock block applications where the owner put a huge amount of boost through a stock 302 block and shifted it really low and was able to crank out 900hp to the wheels. The most infamous was a black SN in Texas that did it consistently. I certainly wouldn't recommend trying this to anyone myself. Some people try stuff just to see what they can get away with. I have a friend with a 94' Camaro LT1. He got it to run 11.0 with stock ported heads with a 396 stroker kit and a stock 2 bolt main. He put an enormous cam on it, and shifted it at 8500 rpms. Every time it would eat the valve train, I would ask him why he didn't get some big AFRs and a smaller cam. He would always laugh and say, "I just want to see how far I can go without buying new heads." He just kept rebuilding the valve train year after year.

    My last stock block stroker engine made it 10 years and 85,000 miles putting 492/635 to the wheels. That's pretty close to 600/700 at the crank, on a stock 93' roller block. It finally broke due to a bearing failure. Totally unrelated to a block failure. Did I get lucky? Was it a really well balanced engine? Who knows. In fact when the new engine builder took some of it apart, he found some errors the original engine builder had made. The wrist pins were too tight, and the valve springs weren't strong enough. I had also used stock bottom end hardware on it. I hope my new engine does that well. I certainly put more money into it, and built it better than the last one. I can say that of the stock block failures I have seen, I would cut the causes into 3rds. One 3rd put way too much power into it and cracked the block. One 3rd put inferior quality Chinese parts in it and cracked the block. One 3rd did everything right and hey, the block just cracked.

    I had a friend run 3 seasons on a stock block 347 on nitrous. He decided to go to a 351W block for the next season when they allowed it. He parked his stock block 347 on an engine stand. It ran similar times to his 347, and then the block cracked after two events. He got rid of that block and built a Man O War 347. It made it half a season, and the block cracked. He pulled the old 2 bolt 347 off the stand and put it back in the car, finished that season, and ran another season after that. Sometimes it's just complete luck of the draw on engines. The car is now parked with that engine. Family and work caught up to him.

    I can tell you exactly why the 351C had 4 bolt mains. It was the performance engine of the time. They were putting that engine in the higher performance cars in the early 70s. Just like I said before, the Ws and Ms were going in the trucks, the Cs were going in the Mustangs.

    Whenever you look at a stock engine, always ask yourself what it was used for in stock form. None of the stock engines Ford has ever used had any substantial block failures. They were all over engineered for their intended purpose.

    The 351W does have more meat in the bottom where it counts. I would say it's good for an extra 100hp. That's my best guess. I can tell you that I have built many engines, and it's hands down cheaper to build a 4 bolt 302 over a stock block 351. The nickel and dime parts to convert a car to a 351 just add up so quick.

    My engine builder hands down refutes that any particular 302 block is better than any other. He's been building serious engines for 40 years now. He has always been adamant that these rumors of Mexican blocks are based on information that has been handed down for 30 years now. Back in 1980 you were better off going out and finding the blocks cast in Mexico because they had a higher nickel content. However, today it is far better to go with a newer block. The killer of SBFs is miles. They are life limited parts, and they fatigue out. When we built my engine, he specifically found a block cast in 2004 with almost no miles on it. He still thought I should go with a 4 bolt main, but he said this block will give me the best odds.

    Ok, now I'm just rambling

    Kurt
     
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  7. A5literMan

    A5literMan Mustang Master

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    Take the engine to a good machine shop and have it checked out. If it's good to go I recommend going with a 408 build. With good Alum heads(minimum of 185cc),link bar roller lifter cam,good induction system and the proper sized exhaust system you'll be able to make well over 500hp and a crap ton of torque. Remember when talking about running a manual trans you'll need at least a TKO 600 with a good clutch etc
     
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  8. NIKwoaC

    NIKwoaC 中國製造

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    @revhead347 I have had a Mexican block in my garage (at one point I had planned to build a Mex-block 347, but plans changed), and I can say without a doubt that they do have more iron in the mains and main caps than the late model roller blocks do, plus they have blind main bolt holes, similar to the 351. I don't know that there is any truth to the nickel content, but I do believe they are a "stronger" 302 block.

    I think, justifiably, that most pro engine builders just don't want to hang their hat on any stock 302 block, that's why a lot of them will avoid saying one is stronger than another. It's too much of a gamble for their reputation, which is understandable.
     
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  9. 1slowfox90

    1slowfox90 Member

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    Thanks for all the information guys. Its great to see different perspectives and I'm glad you all are relatively agreeing on this, makes it easier to make a decision.
     
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  10. madspeed

    madspeed Colonel Mustard
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    Dont forget to read the sticky over on the Corral posted by Woody From Fordstrokers about a flaw that hes discovered with the 351 blicks, and how to identify
     
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  11. A5literMan

    A5literMan Mustang Master

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    That's with the roller blocks if I remember correctly. Not the older blocks
     
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  12. NIKwoaC

    NIKwoaC 中國製造

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    Yea definitely, it's a good reference. It was the first thing I looked for on my roller 351 block (which is still collecting dust and taking up space in my garage, haha). It should be noted that the majority of 351 roller blocks do NOT have that flaw.

    Another good reference over on the corral, again started by Woody, is a thread called "The single number ONE reason a stock 302 block breaks (Pics)", which is a really good reference for anybody questioning the strength of the 302 blocks and the structural difference between the 302 and 351.
     
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  13. 1slowfox90

    1slowfox90 Member

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    Thanks i'll be sure to check it out.
     
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