I didn't have to tap my remanufactured engine for the aftermarket valve cover but I did have to use 2 different size bolts but that doesn't matter -no leaks. See if you can avoid tapping the head because you can tap too deep real quick and have coolant coming out that hole.
1984 jeep cj7, 258 I6, rebuilt T176,rebuilt Dana 300, amc 20 , dana 30, 4.10's Trac-lok in rear , 4.10's detroit soft locker in dana 30, 2.5 inch bds suspension lift, 1 inch polyurethan body mount lift. Line ex. weber carburetor. factory tach. factory clock ,oem replacement speedomter cluster, and oil pressure gauge, factory volt gauge.