Originally posted by dcoffield
So, if I understand what you are saying (before the conversation got 'squishy' ):

I should get the rotating assembly, fit the crank and a piston to
be able to measure the height of the deck from the piston at TDC. This measurement will allow me to compute the actual compression.

Should I do this after the block is machined and decked flat?
Then have the deck machined down to 0 when I have the measurement?
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.