[Jay S]

The later production head I have here appears to have a slightly bigger combustion chamber than 455-4+1. Look at the flat area from the spark plug to the edge of the chamfer at where the machining ends, the head I have is a little wider there. The edge of the chamber looks like it is out further on the head I have. The pic with the marks is the 455-4+1 head.

I cc’d it after I cleaned the head up better and it was 70cc. Lost about 1 cc from what I did earlier, still always to go to get to 66 cc.