I believe the cylinder heads play role in cubic capacity of an engine. I have an engine I got with 2 different heads. One has a deeper "bowl" than the other and has 8 fins whereas the other 7. I can't tell capacity of either but wish to have that with most.
How can I tell capacity of a cylinder head?
make a disc of Plexiglas the size of the cylinder. Put a 1/2 hole in the center. With valves in seats (springs not needed) place the disc in the cylinder opening in the head and pour oil through the hole into the combustion chamber until oil is touching the Plexiglas and there is no air. Measure the CC's of oil for each combustion chamber and compare. That tells the volume of the combustion chamber.
Wow!.... I'm yet to try that. I'm gearing for a rebuild...good thing, I know the capacity to the heads I'm working with....so I'll do the procedure and counter-check results against the known.