4 bolt main caps on 351W

Does anyone have experience with splayed 4 bolt main caps on a 69 Windsor block, or other years for that matter? The last 351 W broke the main webs out. I believe it was a result of cap walk. We have another 69 block, 408, that has a girdle. I am going to check the bottom end of this engine this Winter. I know of one guy at our local track that ran the splayed 4 bolt caps and he ran in the 5.50's I think, 1/8th mile, on nitrous. The next engine will probably make in the neighborhood of 650-700hp. If anyone has ever used these with sucess, I would like to hear about it. Thank you.

I just did a D4 block with splayed caps and a half fill.(425ci)
Its not going into the car till spring so I cant really say if it helps much or not.

A guy who has a shop in TN knows about this subject and can get it done. Says they can stand some power with that configuration.

Let me know if you want his info and I'll get it for you.

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<font size=-1>[ This Message was edited by: BoomerRacing on 11/28/06 4:50am ]</font>

There are several companies that sell billet splayed caps for 351W's -- cant recall the name but there was one at the PRI Show who had them for every Ford since the Y-Block.

But you have to be careful that the holes you drill in the webs to mount the splayed bolts don't weaken the web.

IMHO you might want to think about one of the Ford Racing blocks if you are putting enough oomph into one to blow the main webs out.

Production blocks are gray iron, and have only a limited service life. They are good for, probably, half again the peak rated hp of their strongest configuration without serious damage. In a 351 W, that would be somewhere in the 450-500 hp neighborhood. Yes I know all the magazines publish stories about 600 hp Windsors, but think about it -- that was one pull or at best a series of a few.

A purpose designed and cast race block will have lots more beef where it counts, have a more stable cylinder wall and a more stable deck for better sealing, plus it will keep everything else from wiggling around and causing a catastrophic failure.

In the end, it is cost-competitive with all the 'trick' machining operations you would need to do to a boneyard production block to let it live for even a little while in a high hp / high load environment (and let me guess, the squeeze was on when it went bang?)

You can get the parts, but you have to look at the whole picture before you fork over the $$$$$$$$$$$$$$$.

Good luck!
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Boy oh boy...I'm hashing this around right now. I've got 3 blocks...a C9, a E4 and an E9. The C9 is already .060 (actually .055 right now..we didn't take it all the way yet to see if it'd clean up at .060). And yes, I am making enough to kill a 351w block. Killed 2 so far; blew the mains out of both.

A friend of mine has all the necessary machining equipment to do up a splayed cap motor. We bored it on his equipment. I may just spring for it as I'll only be out the price of the caps and the line bore cost...the rest of the machining we can do at his shop in spare time.

Only problem I'm running into is that the early ones are 9.48 deck. Well my regular 415" combo is 6.250 Rods and 1.245 flat tops. That puts me at 9.495 stack height...puts the pistons out a MINIMUM of .015" before any resurfacing. Probably a little more than I want to go. I see that Diamond makes a set of high compression pistons for a low-deck 408 combo....so I may look into that, but I like the pistons I'm using as they are very light and very strong for their weight. Plus the ring package doesn't induce much drag. Engine turns over on the stand (no heads on the motor) at 8 lb-ft initially. But if I can get away with low-drag rings on the Diamonds, I may try it. Should be around 14:1 compression though...where I'm at 12.2 right now so there may be a slight boost in performance.

Who knows. I might just go for another E4 block, filled, with 2 bolt caps and the regular stuff. Need to get somethign going pretty soon though as the one in the car now has about 55 passes on it. They seem to go 250-300 before the mains let go, at least in my combination..and I am in no way easy on them! Full bore every pass, 7000 shift, 7100 at the stripe...burnouts are usually kept under 5000 but it doesnt' seem to make a difference. They don't last forever.

Aftermarket blocks? Well...they all cost $2K and above. I've built BOTH of the last 2 engines including repair to the heads, converter and transmission....for just a tick over that. And what happens when a crank breaks or a rod lets go in that high $$$ block? There is a feeling when stuff like that happens....your stomach ends up just below your heart and you think to yourself "I wish I had just used a cheap block"....

Believe me, I've been there &amp; done that. NONE of them last forever in the type environment that I put them in.
[addsig]

keep building them like you guys are and I'm sure your luck will change and they will stay together.