The 76ers have been through a recent implosion and most likely have some bent valves. They may clean up with cutting the seats for oversized valves and they may not. If I could spend the same money and do this work on the 64s and lose 3.5 to 5 cc's in the chamber the DCR would fall in line. I would also be using a set of heads that have no impact history on them. The way the rest of the motor went up I am a little shy about using them until I can afford to really have them tested and machined.
I know that as I push the edge for heat and detonation I need to keep this motor cool. What do you think of oversize the exhaust to 1.625 instead of 1.6 or use a 1.6 rocker and use a 160 or 170* thermostat?