Years ago I measured the compression ratio of my C Rapide which was fitted with the clubs 7.3:1 Omega pistons, and they came out at 7.2:1 with a volume of 80.5 cc.
I have never measured an 8:1 piston.
Don't forget its not just the cylinder head volume that counts as the shape of the top of the piston also affects it. My measurement was with the engine on the bench and supported so the spark plug hole was pointing directly up and the piston was at TDC with grease around it to seal to the bore. I measured the amount of oil it took to fill the combustion chamber to the bottom of the plug threads. I was more curious if both cylinders were the same rather than the actual figure.
Simon
I have never measured an 8:1 piston.
Don't forget its not just the cylinder head volume that counts as the shape of the top of the piston also affects it. My measurement was with the engine on the bench and supported so the spark plug hole was pointing directly up and the piston was at TDC with grease around it to seal to the bore. I measured the amount of oil it took to fill the combustion chamber to the bottom of the plug threads. I was more curious if both cylinders were the same rather than the actual figure.
Simon