Main Caps on 95 LT1 block. Options are 4 bolt straight (If I can get my hands on some used factory corvette 4 bolt mains) or after market 4 bolt splayed caps. I remember eons ago there being a debate about straight or splayed and block material availability. I plan on pushing heavy boost. I AM going to try to rip that forged crank through the block. Which setup and what aftermarket manufacturer's caps would hold out to that type of stress the longest if not the OEM straight caps? I've never seen or heard of LT1 caps failing weather it be 2 or 4 bolt. Mostly just heard about crank's breaking but still it's piece of mind. I've heard about cap failures in the aluminum LSX's but ours are iron born blocks so I of course expect them to be more rugged.

 

The shop that built my Formula’s LT1 stroker 20 years ago recommended Pro-Gram Engineering caps. They built several high boost 1,000+ HP LT1 engines over the years, never had a failure. My nitrous setup (only 800hp/800lb-ft) used a splayed conversion on my 2-bolt F-Body block. They did a buddy on mines 97 SS 1,125hp at the flywheel, 9.05@155mph). He started with a Corvette straight 4-bolt block, and used the Pro-Gram straight 4-bolt main caps.

The shop (Second Street Speed in Perkasie, PA) spent a lot of time measuring and testing the LT1 block. Their conclusion was that GM had incorporated the strength of the Bowtie block, and had put extra meat in the correct places for the straight main bolt configuration. Unfortunately they didn’t tell me that when I told them I wanted splayed mains. Didn’t really matter, 20+ years later the car's new owner is still flogging it with the 300-shot. The Callies Stealth crank and the Oliver billet rods are holding up as well.

 

Well I think you for your insight. That's sounds like some good information. Guess the best part about working on an older car is "time" has proven what will and won't work.