One more question on this subject. I received my UFC 5/8 inch tap from McMaster Car today and it mikes out at .63 inch on outside of the cutting edges. The temp and
oil sender fittings mike out at .66 inch OD. Does a .03 inch interference fit seem unusual for a treaded fitting like this? I assumed they would be closer in diameter or identical and I definately don't want to accidently crack this old intake.
Thanks