I'm adding a Lunati rotating assembly(383) to my 95 Trans Am and a single or twin turbo will be behind that. I'd like to build the bottom end to hold possibly up to 650rwhp. I'd also like to convert the stock 2-bolt main to a 4-bolt splayed cap. Which caps will be strong enough? Pro Gram? I think Pro Gram only makes caps 2,3, and 4 for LT1s? If so, what sould I do about cap #1 and #5? Arp studs on 1 and 5 and leave them 2-bolt? Thanks.

 

Yeah, I think most people leave 1 and 5 as 2-bolt mains. I've heard Pro Gram is the best. I actually have my old stock 4-bolt block that's a little messed up, but it can be fixed if you want to use that instead.

 

Pro-Gram makes both a billet 2-bolt and a billet 4-bolt cap for the front main - SB350F/SB350F4B. But at the level you are talking about, all you need is the center cap conversion. I'm running the Pro-Gram centers only at the 800 flywheelHP level.