I am going to bluid either a 383 or 396 this winter and would like a 4 bolt main block. I have not been able to find any yet. Is it possible to change a 2 bolt to a 4 bolt? If not how much power will a 2 bolt block handle?

Thanks
Augi

 

You can go 4 bolt mains on the 3 center mains....cost would be about $300-$400 for billet caps installed. My machine shop put in cast 4 bolt caps for $75 total.

 

If you're going to make up over 500hp NA, then I'd go ahead and spend the $ on either a 4bolt block, or converting a 2bolt. I don't know what used 4bolt blocks go for, but if you convert to splayed 4bolt (3 centers), you'll spend $200 on caps, $70 on studs, $175-200 to have it align bored, and then whatever your machinist wants to charge for 2-3hrs labor.

If you cant afford that, most people would be fine with 2bolt stuff & studs IMO, as most are only making up to around 450hp.