heads

Nope. Not without klnowing what engine you're talking. Most open chamber 340/360 "J" style, including X, J, O, 915, and the later ones are all somewhere around 74-76 factory, sometimes more. The 318 open chambers are a little more accurate than the larger ones, IIRC closer to 60ccs. The big blocks, from 906-up, all are huge, on the order of 87-94+ again depending on the mood of the guy cutting seats and the casting. They are always bigger. And more importantly, so is the deck hieght of your block. So those catalog numbers are never true. Best bet is pick the piston you want, and tell the machinist to blueprint everything.