The edge of an intake valve on a stock magnum is like .060 from the surface of the head, a fel pro head gasket .s .039 thick that gives around .100 clearance at TDC and a short duration cam like you would do for this motor are not gonna be open that high at TDC now throw in a VJ and you got plenty of room and if not you certainly would not need the big valve releifs of the KB 167 or even a stock piston, mabey a nick of a notch but not much. Obviously mock it all up and check but I bet it would not need much if any notch