HELP! Need 318 Head Suggestion (info provided)

I have read from many different sources that 318 heads on average are in the 62-64 cc range sometimes less, the 340/360 heads had the 74cc and up combustion chambers. I gotta get me a burette and cc my heads I have. They are pre-air port so they have to be older ones. From the casting number they were used 69-74.