I have a .030 over 454 with flattop pistons. Sadly,they are .032 below deck. Even more sad is the 215 heads that I have cc'd are a whopping 117cc!!! Stock, they are closed chamber at about 101cc but they have been ported, bigger valves and shrouded. The unshrouding added cc's ...16cc to be exact. I put this on the desktop with a .021 gasket and only yield 8.4 to 1. If i shave .030 off the heads, about what would be my new cc chamber volume? Is there a way to find this out? I would like to get about 9 to 1. I also have 781 heads but i cc'd them and found a worse 119cc. I would like to use the 1968 215 heads because they have 2.19/1.88 stainless valves, and about $1400 of port work and 4 angle. With the low compression, I would probably be better off with the 781's but i would rather get the compression up as much as I can without changing the piston. Thanks for any input.