My son and I ported his 462 castings and CCd the intake ports at 169 and combustion chambers at 61. We cc'd the intake port with a valve installed. My question is- do all aftermarket head manufacturers cc their heads with a valve installed or some do and some don't? Valve shape would also play an important factor in how much area it displaces within the port. This may seem like a dumb question but does anyone know? I also remember reading all of CHP magazine's head testing and they came up with port sizes on many of the heads far different than what the manufacturer claimed.

Far as I know they are all done with the valves in. I have never seen or heard of doing it any other way.
Don't really know how you would unless it was in the design stage on the computer.

As for "manufacturers claims",,,, it's a "close" approximation in a lot of cases :D
Gotta remember, it is a casting & you can only get so close but some of the numbers I have seen compared to what I measured do seem to stretch the definition of "close",, at least my definition ;)