if your going to build it from the ground up as a performance build do yourself a favor and buck up the money to get some compression in it. off the shelf pistons are usually in the 8.0-8.5 range with stock heads. my 383 runs hard but im at about 8.8:1 compression with speed pro pistons and 84cc heads. its been proven here that head flow trumps compression but it is easier to make an optimal combination with higher compression. id shoot for 9.5-10:1 with iron heads and 10-10.5: with alum heads. i have been very tempted to rip my 383 back down and have a set of 11:1 custom pistons made up and toss in a solid roller cam. then it would really be a terror.
​