I have a set of #061 heads that were cast in 1967. They have the large valves with a unique open chamber design. The rocker studs are pressed in and also pinned. My two questions: Did the factory ever pin the studs? What is the correct cc of the chambers? I have seen several web sites that give the chamber size as 72cc, 75cc, 80cc. When I tried to measure the chambers with a cc syringe it seemed to be aprox. 77cc. These heads do not appear to ever have had a valve job. Any one know the straight scoop about these chambers?