Thread: 4-bolt main or not

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any the number of caps always stay the same. 4

Not necessarily, depends on the engine. V-8's generally have 5, I-6's, V-6's, V-10's and V-12's are all different.

Great pics, Denny! I really like the girdles, been using them ever since they came out, and before that we built our own cap supports for the Windsors from a piece of bar stock and a bit of flat milling on the cap. The billet girdles are soooooo nice and sooooo much easier then building your own!!!!!

With splayed outer bolts, billet caps, and a billet girdle if it doesn't stay together, then something is seriously wrong!!!!

Hey there here is a link to a site that will tell you pretty much everything you would like to know about your SBC hope it helps ya it has helped me alot when buying used motors.
http://www.nastyz28.com/sbchevy/sblock.html

dennyw is spot on..the 2 bolt from the 4 bolt both brake in the same spot most of the time.. the 4 bolt helps cap walk and some bearing issues and thats about it..

Denny has it more "ON" than you know. The point about 4 bolt mains seem to go over everybody's head and the new questions anew themselves. Now, Denny has actually supplied the pics we have been beating into the ground for a long while. (No offense Denny). The 4 bolt set up is contribed as a saviour to your woes. It is clear that it is not understood very well. The weak point is the "bridge" (radius, or "arc" if you will), not the amount of bolts to control cap ""walk". The pics show exactly where your defects are and it's not in the mating surface of the cap to block area. Most novice and wnanbee's think that the bolts you have, the stronger the webbing in the block is............nope! Concentrate on the weakness and strengths of your block and cure the weakest link, not what some hotrod magizine wrote. You wanna stop cap walk? Splay the outer bolts to the angle of the cylinders, and this is elementary basics for longevity. Not to leave you out Dave, you're right, splay 'em and keep it "square". Then there's something seriously wrong if it goes away. "Geometry, Geometry....................................."

WELLthe way i see it . the cap that is crack was a cast steel/iron cap. a billet steel cap you would not do that to. BUT a 4 bolt cap just adds two more holes were you really do not want them .this will not make it stronger in the block web as for the cap not walking with the add bolts ? i seen them move the caps the bolts just hold the cap in the block the holes for cap are bigger so the bolts go thru it .if they were held in by the side of the bolt they would break the bolt or stud is not made to take side load and to stop the cap from moving side to side justs to keep the cap from pulling down . the cap need to fit the rester of the block that helps keep the bearing and cap from moving side to side. if the cap stay flat and not springs up . the make up of the cap helps to .cast steel /iron. or better ductile iron . steel forged /billet . the crank is trying to pull the cap down this springs the caps then may bow them up were there is not any bolts .like denny showed . then bolts or studs will not help to lock the cap in the block... the cap must lock in to the block.....with out no bolts . the bolt do not do this what can help is a big dowel on each side of the cap or pin not just a small 1/4 pin or an open dowel or split one but a soild pin in the middle of the two bolts that way you use the bolts to hold the cap up on the block and the soild pins and using another surface to hold the cap from sprining ? keep the cap from sprining down and getting loose and skidding side to side . that the way i see it

Amen! More attitudes can be expressed, but that pretty much covers the street attitude. Thanks Pat.

When I use "splayed steel caps" I like to use about the cheapest ones out there.
The reason being no matter what "splayed steel cap" you use it will always be stronger than the cast iron around it.