Originally posted by camaro_fever68
No, you can use deck height for that computation, with a 0 deck height your pistons are 10:4 with a 64cc head. You would only need to calculate if you didn't know your piston part number or they didn't have it listed in their chart. Dart does make that head in 72cc I'll calculate that for you post it in a bit.
A good estimate would be around 9.5 to 1.