Plug a smog hole

A trick for keeping the tap "straight" into the hole is to take a piece of aluminum, steel, even a block of hardwood, that is 1 to 1 1/2 inch thick, drill a hole thru it that is just the OD of the tap. That will hold the tap so it goes straight into the hole.

I suggest this on the assumption you have a drill press; if you don't don't worry about it, just start the tap as square as you can.

Good luck!