Helicoil

Jack, "You can do it". I helicoiled 3 of the holes on the exhaust sides of my heads, 2 on one head & 1 on the other. I used my drill press vise & some shims to make sure the face was level, plumb & square to the collet. I drilled them & slowed the press down to its lowest speed to tap the holes. I made sure to use green LOCTITE on the coils to make sure the stay. If I can do it, you can. LOL