[70lemansport]

Hello all,
i have a 70 lemans sport conv. with its 350 about to get rebuilt. the heads are #11's and are 73cc heads i beleive. i am trying to find out( without pulling the heads yet) if the pistons have valve releifs(i don't think so) and if so how many cc's. also what was the stock head gasket thickness? Im trying to calculate my CR and i've read its a 8.8 but my calculations are giving me 9.32. im using 3.875 bore-3.75 stroke-73cc heads-i put a gasket thickness of .05-a deck height of .023 and 0 cc's-/+ via dome of vavle releif. What's going wrong? the calc im using ishttp://www.thepontiactransampage.com/compcalc.html
Thanks