Alan, if you use a pipe tap make sure the threads on the fitting don’t shank out. You want the fitting to tighten up with most of the threads in the block but some thread showing. If you need sealer it’s not tapped right but teflon paste is ok.
FAA certified jet engine and aircraft technician,
Nicholson Speedway class champion 2001,
Yamaha KT100 Service Center,
41 years karting experience