Thinking about the mopar aluminum heads(63cc)for a commando crate engine with comp xe268,stock compression maybe 9:2?not 100% sure as motor never apart.Will this be enough comp. for these?installed should be 10:2ish.don't want edelbrocks(long story) any advice,4200lb 77 custom 100,mopar muscle car convertor crappy 3:21 gears.I know,I know gears,gears,eventually.