383 deck

All parts are machined with different tolerances. So every case is possibly different, I had a 440 block decked 10 thou and the intake needed milled to fit properly. But the heads were also shaved 5 thou so that played part too,
But depending on how much needs taken off it can also change pushrod length, also be sure to check p2v clearance since the piston will be closer to zero deck when milled.