Intake Leak

Any time you you do more than a clean up cut (4 or 5 thousandths) on a block deck or head surface you also need to cut the intake surface of the head. This is not a straight 1 to 1 cut but is a ratio. I think the magic multiplier is 1.6. I could be wrong on that so check with a competent machinist before cutting your heads. For example, using my multiplier, if you cut the deck surface .015" you would need to cut the intake surface .024". Oh, by the way, cutting the intake manifold only makes the mismatch worse...