Originally Posted by smith9300
If I put the 350 heads on it would it have to run premium gas and its a bone stock 400 when I got it it didn't have a cam the bottom end is good but I just want it to have some good torque and I dont want the heads to be the thing that holds it back but its going in a 85 Chevy c20 lifted bout 6 inches it deffently shows its age but I got it as a gift and its my project
If the stock pistons are going to be reused, AND if the dish is 24cc like the 400 often used stock, the 64cc chamber size will put the compression ratio (CR) at about 9.6:1 using a 0.040" quench.
But if you want to use 64cc heads, at least go w/Vortecs
. The old small chamber SBC heads are ~45-plus y/o and will usually need guides, seats, springs possibly valves, milling, etc. Not worth all that. Or just go w/aftermarket if the budget allows.