If you go with the KB400's I wouldn't bother doing anymore than a clean up cut to square the decks , if you zero deck it then you also need to cut either the heads or the intake to make up for the at minimum .024 off the block deck , that is the same as cutting .024 off the heads , the intake surface needs to be cut also, and don't forget the valley end rails will also need to be cut. But once you either cut just the heads or the intake that part is now married to that 383 block , otherwise later you will need to cut something to make it fit on another block.

I'm getting 10.0 with my 383 using 906's, Diamond flat top at zero , 3cc valve reliefs and heads cut to 79.8cc.