I was wondering what everyone considers the best option for converting an LT1 engine from 2 bolt mains to 4 bolt mains. Are the stock GM nodular caps strong enough or should I go with billet CNC mains. GM Performance Parts billet mains are 54.00 each, and they also make a billet 2 bolt front main. Plan on making 525 rwhp with a blower. What does everyone else think?

 

525rwhp, you'd probably be fine with a 2 bolt. My friend is running a 355 stroker in an old Grand Prix with a 450 shot on a 2 bolt main.

 

J&J,

If you want to find out what cap walk is and learn how to change main bearings alot then the 2 bolt is your choice. About 550hp at the flywheel is the max you should do. 500hp is safe.

525rwhp is a lofty goal if you don't have it dialed in right. I really only see blower cars on both ends of the spectrum, 390-400rwhp and 700rwhp. You sure you're going to get all of that 525rwhp?

As for the 4 bolt caps, you can do the nodular ones but don't do the GM 8620 caps because you can pick up other sets for less. They are nice caps, I've used them on Bowtie blocks before. But their are many aftermarket caps out there that will do the job.

Bret

 

I think 525 rwhp range will be easily attainable. I figure a solid bottom end, ported LT1 heads with 2.00/1.56 valves, and 12 psi of intercooled boost. It can't be that uncommon making that type of power with a procharger. Hell you can make 400-450 at the wheels with a mild-medium 383 setup

 

Yeah I know, but that's good planning.

12psi is alot of cylinder pressure and you have to spin the **** out of the procharger to do that, which will comprimise blower life. Good luck sorting out the belt slippage and all the other fun blower stuff. 600+hp needs alot of attention to pull off.

Bret

 

Like bret said.. lots of aftermarket caps out there that'll do the job easily. Most 3 center sets seem to be ~$200 & some ARP studs will probably run you $65-70ish. By the time you have a machinist convert the block, youll probably spend $550-650 total on it.