For the racer that likes to fabricate and build their own oil, fuel or puke tanks RBS carries a complete line of steel weld on male AN bungs. Made from steel so painting or powder coating after welding is no issue for the do it yourselfer. Male bung has a 37 degree JIC flare to work with industry standard female fittings.
Bungs have small step on the back side which allow the bung to register in the hole and makes it easy for alignment and to be welded from both sides if the racer chooses.