MadMac,
Combustion chamber size isn't measured in cc's its measured by the ratio to which the pisont compresses the air fuel mix in the cylinder
He wants to know the actually clearance volume in CC.
The easiest and most accurate way to measure this, and many will disagree, but it works fo me, is to bolt the head onto the block with engine set to compression TDC and using a BURRETTE measure the amount of fluid required to fill up to the spark plug hole.
That will give you asn accurate clearance volume, then you just need to add your swept volume into the equasion and bobs your mothers brother
