I can tap it. I can weld it.
While you may want it tapped, it will be stronger if it's welded
and/or a nut on the inside of the oil pan fitting, since the oil pan
metal is thin. I would also seal it tightly around the nut.
I would not drill/tap into a pan that's still on the car since I
don't want any metal shavings in an oil pan. -Bob