Yes, their valves. I decided to check them because the assembled cnc Heads don't show any chamber work, at there's no reason they would be bigger unless they were cast that way.
@Bobzilla reminded me that he got a set with cnc chambers, they were odd because according to the SM sure you can get that feature on only on PN, a bare head. I'm guessing that's where the 68cc came from, but it doesn't apply to any of the cast chamber parts.
I did multiple chambers and two intake ports. They averaged out to 65/190 respectively.
When Dwayne Porter had mine, we discussed going up a size or two on they intake valves, the throat diameter was a bit big for the 2.02 valves. But after discussing the extra cost in parts and chamber work I decided to pass. My"budget" heads were getting up into the 1700 range.
