Daze, get outta my head I have a FordStrokers 427 DART longblock in my Lightning, it replaced that darned flat tappet 351. 

Anyway I've dealt with Woody, he's a standup guy. I imagine what you are saying is true, but I also imagine he's not going to stake his reputation on that. Most people picking up engines from him are going to push them really hard (I am and that's the reason for the DART block) with power-adders and such.

Current state of affairs with the truck I keep talking about 

Last edited by Raymond_B (2/17/2018 6:56 PM)

Daze wrote:

Raymond_B wrote:

Anyway I've dealt with Woody, he's a standup guy. I imagine what you are saying is true, but I also imagine he's not going to stake his reputation on that. Most people picking up engines from him are going to push them really hard (I am and that's the reason for the DART block) with power-adders and such.

I have have heard nothing but good things about fordstroker and I don't blame him for not rebuilding one of these blocks, especially all he does is high power strokers.  I also think his his post is a good one to get the info out there his concerns are valid but IMHO negligible and not worth the panic depending on the aplication.  
 

"Not worth the panic", I like that. You're right, a lot of my buddies always use the old adage DYOR, Do Your Own Research... I am sure in a well mannered solidly installed combo it would be fine.
 

Last edited by Raymond_B (2/17/2018 9:04 PM)

There are two separate issues here.  The first is if you are building a high power engine than this block cracked or not is not your best choice.  I totally agree that Woody totally made the correct decision in not rebuilding these blocks.  For my business personally I would never let anything but the best go out to a customer as its my reputation on the line.  I also think that letting people know about this crack is good info to get out there so those building a performance 351 know what to look for.  

With that said I think his post was kind of like yelling "fire" in a movie theatre.  He has never seen one of these fail, in other words all the engine blocks he has seen like this came into the shop had nothing more than a crack.  Also Woody made that statement that a lot of builders probably wouldn't even notice the crack as it is not a normal place to check so there are probably a lot of 351s out there built up that have that crack. I spent a lot of time on-line looking, and I could not find a singe instance where this crack ran and caused issues, not one.  People talk about 302s coming apart and most of those cases can be attributed to boring the block out further than they should, the 302 is also a much weaker block than the 351 from the factory and is being pushed higher than it should be IMHO.

Also as I said before two things cause cracks on a running engine the first is heat/thermal cycle and the second is stress from combustion.  Being in the center of the block heat is obviously not the cause as the center of the engine will cool slower than any other part of the engine and the hottest parts will be at the cylinders and especially at the top of the block and the heads.  As far as combustion stress again the stress points are going to be at the mains and the cylinder walls not the top of the cam journal where the lifter valley and the cam journals meet.  In fact that part of the block probably has a better strength to stress ratio than anywhere else in the block.  I do not see any way that either of these causes would apply in this case.

"When you have eliminated the impossible, whatever remains, however improbable, must be the truth"

That leaves the obvious cause being related to the machining, so  it happened at the factory.  An EFI engine can easily last 200K to 300K miles.  Just to be safe lets say 200K miles per engine.  that means for every 5 of these engines that are cracked thats a million miles in its life.  Woody said 1/10 blocks have this crack.  I don't know the production numbers but at 1 out of only 10 only 50,000 of these blocks would need to be produced to have over a billion miles on cracked blocks.  Again I could not find one instance of a a failure.  

I think this crack is something to be aware of especially if you are building a performance 351 but based on real world data I do not believe this crack is much to worry about in most applications.

I ran into a similar situation when researching Jag IRS for my Mustang.  The upright hubs are cast aluminum and quite a few hubs were showing up with a crack in the lower webbing.  It was always in the same spot and had a lot people worried about the parts.  After a lot of research and panic from the Jaguar community (like the 351 not one failure documented) the general consensus was that the crack happened at the factory and was not a big deal, something to be aware of so you could make an informed decision .  I was thank full that neither of my hubs were cracked and I don't think I would have risked it had there been a crack given th performance nature of my appliation, but the same thing happened there that has happened in regards to the 351 crack, a lot of concern for a minimal issue.  

The info is there so people can make an educated decision that will best suit their needs, but unfortunately it has become a a decision forced upon them out of fear and panic.

Carefully thought out, but there's a couple things I think you may be missing:

First, an absence of proof is not a proof of absence.  The primary problem I see is that just because there is no dearth of cases where this crack seemingly caused a failure doesn't mean that's the case.  Its possible that when these engines have failed it was not attributed to this crack for a variety of reasons.  Obviously this precludes the classic 302 block splitting in half outcome, but there could be other less obvious problems caused by this.

Second, In stock form this may well be an acceptable flaw.  Keep in mind that these engines were built for low speed torque in trucks, not high RPM, high HP use in cars.  Its quite possible that the crack only becomes an issue when the engines are rebuilt for use other than as the factory intended.  High performance engines fail all the time, so again, we get into the scenario where the crack caused a failure not attributed to the crack.

Third, if Woody is actively avoiding these blocks that tells me all I need to know.  If he's just cautious and checks them in that area for the crack that's another situation.  I do the same work for a customer I would do for myself.  Its one of the reasons why I'm not a mechanic for a living; I'd never make any money.  If a professional engine builder sees this as a problem I'd at the very least check the block for the crack before deciding to blindly roll the dice. 

A bit of Devil's Advocate for sure, but all in all worth thinking about. 

I will say that the internet has a ton of good information on it.  A fair amount of malarky too, but a lot of good info.  There are definitely instances where a stuff on the internet causes people to get gun shy about stuff there's no reason to be gun shy about.  This may well be one of those cases.  In the end its not my engine.  I already know what I'd do (check it and build it if the crack wasn't there, find another block if it was).  You've got an added factor there though: scarcity.  Around here I can go find ten of those engines with no problem, and pay a reasonable price for them.  I'm sure that's a factor in your decision too, just be sure you're giving it the weight it deserves and not trying to influence your decision over concern of not being able to find another reasonably priced block if this one is indeed cracked. 

I think this is exactly how the net should be used.  You posted some information about a potential problem.  There was some debate and discussion conducted in a very adult manner about the issue.  A consensus was reached, if not an actual conclusion.  The information now exists forever.

I'll be interested to hear what you uncover as you move forward with this project, the decisions you ultimately make, and the outcome. 

I am working on an '89 GT right now that was supposed to have a stock bottom end 5.0 with a Trick Flow top end kit on it.  I've got a 100k mile stock bottom end from a buddy's '89 that there's nothing wrong with, but I just can't leave it alone.  I've got to go through it, and if I've got to go through it I'm building a 331, if for nothing else to have a comparison piece to the 347 I'm building for my '67.  Oh well, at least I can afford this stuff now.  When I was younger it was all big dreams but Burger King budget.  Cars: the only addiction of which I have no desire to be cured

josh-kebob wrote:

Sorry fella's but, the decision to rebuild an engine is pretty simple for me.........
-Engine block has zero cracks ---Rebuild it
-Engine block cracked -- Recycle it
 

FYIFord's own Woody!

I agree with josh. Due diligence is key.