Welcome to the V-Mar Racing engine computer.
This COOL little Java Applet lets you figure out your Displacement, and/or Compression ratio. If you would like to know what CC's or what Deck Height will get you a particular Compression Ratio, it will solve that for you as well.
* note: The Deck Height measurement is from the top of the block or cylinder down to the top of the piston, if the piston sticks up above the top of the block or cylinder, the deck height will be negative ( -.010") Remember to figure in the thickness of your headgasket (if you have one) into your deck height. (if your deck is -.020, and your head gasket is .100" thick then your deck would be .100 + (-.020) = .080 ..... get it?) If your deck is -.100 and your head gasket is .050" thick, I think you may have a problem. .050 + (-.100) = -.050* another note: If you have pop up pistons, you will need to measure the cc's lost by the dome of the piston and subtract it from your Combustion Chamber CC's measurement, or add the cc's if you have a dished piston.
The Fine Print : This app was written entirely by me, vince@vmar.com, I was going to put in all kinds of traps, so you couldn't have an engine with a 6" bore, and a 1" stroke with 3" of deck height etc..., but decided to just let the app do any calculation you ask it to. Therfore you may get results that are unrealistic (but accurate). For example if the program tells you to run a .010" deck height to get 12:1 compression, it simply means that 12:1 compression with your motor is unrealistic. If you have a question on a particular combination you can ask me, and if I can help you out I will.