57 cc is NHRA minimum allowable. I've done quite a few 273 heads and it takes .040 to get to 57 cc on the largest chamber. Then .038 on the intake side of the head. I can use any intake and not have to worry about if it will fit and seal. Or try to remember or figure out what I or someone else did. It also takes .040 off J heads to get to min NHRA specs. As for the rest I do not have any personal experience.
