Originally Posted by
JIMinPHX
You’re in luck because it’s in aluminum. Put a 5/16 nut over the hole & stick a mig welder down in the center of it & weld the tap to the nut. Don't be shy with the heat. About 5 seconds after the orange glow goes away, turn it out with a wrench. Steel mig wire doesn’t stick to Aluminum & the heat from the weld will expand the aluminum & loosen the tap. Aluminum expands much more than steel does when you heat it. I’ve done this for broken exhaust bolts on Harley shovelheads several times. It works great.