How to check Combustion size?

[dlampe]

I have the yates style combustion chambers in my blue thunder heads. Does anyone know what the combustion chamber size is? My pistons had a 9cc dome but had to be machined to fit the chambers. I am trying to establish a static compression ratio. Is there a way to do this with fluid while the motor is in the car? I was thinking about filling the chamber with something at TDC and measuring the cc's. Can you do that and if so, how?

[427sharpe]

Sorry, but can't be done in the car. No way to accurately fill the chamber with fluid that way. To get an accurate measurement, you need to cc the heads (upside down on a table), then account for gasket crush (listed on most head gasket spec sheets), then figure combustion chamber size (mathematic only). THEN add it all up, figure stroke for swept volume and finalize the figures. The BT heads are popular enough that I am sure the mfg can supply the numbers and the rest can be gleaned from mfg websites and a calculator!