Upgrading stock 1971 318 heads

When i cc'd those heads...the open chamber heads were around 68cc the early closed chamber heads were around 66cc and the 302 heads I pulled off a factory 140k motor measured up as the advertised at 64cc.

Problem here is everyone will give a different cc, what they found or heard or believe to be correct....but the fact is they varied to a degree from the factory ...as do people's memory and testing accuracy.