[QUOTE=footjoy;6073728]Ok so mine are 1970 heads with 87cc chambers can I take 7 cc off these heads?/QUOTE]
Without knowing all your EXACT specs, all you can do is plug in what you think they might be.
http://www.wallaceracing.com/cr_test2.php
400 std bore, 3.75 stroke, 87cc chambers, 6.6cc valve reliefs, .045 x 4.3 gaskets, & .020 deck height. Calculator says 8.54 CR.
Remove 7cc from the chambers & the calculator says 9.06 CR.