build my 440 to 600hp cheap

No problem..As far as milling, I cant recall how much you meed to mill to get 1 cc smaller on edelbrocks..I know Indy SRs are .010 = -1cc..so you'd need to mill the 84cc down .090..I would have a chamber cc'd anyway, just to see where they are..If Muscle Motors freshened them, they more than likely touched up the surface by milling anyway. Generally, cutting more than .050, will require cutting the intake to fit, but also will need shorter pushrods, to correct the geometry issues that come about. It's no big deal, unless you like to swap intakes regularly. I would go no lower than 11:1.