looking to find the secret formula for finding comp. ratio on a motor

There's a nice one at www.kb-silvolite.com

I need to find it by cc-ing the combustion chamber I didn't want to pull heads and such

The only way to be accurate is to pull a head and c.c a chamber, measure the distance the piston is in the hole, and the pistons volume. Any other way is simply a guess if all of the above numbers are not known