[gmonde]

bill your on the right track but use a bolt instead of a nut (with the manifold off) wire wheel the broken stud ,take your mig and turn up the amps ,line up the wire with the center of the broken bolt and perform a stitch action on the broken bolt ,watching the red hot just start to cool,keep it pink ,,,once you have a build up exposed ,take a 1 inch 3/8 bolt weld it to the builtup material top side and bottom side,,with a little heat on the exhaust port and a 9/16 socket on a 3/8 breaker bar gently rock the bar back and forth until you see some move ment ,,,be patient it will come out,you might have to re weld the bolt a few times but its worth the effort ,,,no miss drilled holes and no messed up threads

worked at a midas in my early days and worked on commission gmonde