Mopar Cast Valve Covers Problem

Use a 1" long button head allen screw. Every MP cast valve cover we have is very tight there on iron heads because of the angle the threaded hole is tapped. On the iron head the sealing surface at the bolt holes is at an angle and the threads are tapped perpendicular to the angled surface. The bolt points away from the valve cover on the top and into the valve cover on the bottom. The aluminum head holes are less of a problem because they are tapped differently. We keep a supply of stainless steel button head screws and stainless steel 1/4" washers with an outside diameter of 1/2" to use on all our MP cast aluminum valve covers.