Yeah i've had to weld nut on bolts heaps before. Mainly exhaust manifolds and exhaust studs snapped in heads. It saves time when studs snap on the flange. Saves having to pull the manifolds out.

lol when i get a chance i will take a photo of the bolt with the spanner welded to it, you have to see it. the EB ED falcon 4.0 i6 is a great motor, specially the overhead cam , i love these smooth quiet engines. specialy when they have been enhanced! this was the only hassel i had doing the head gasket. just hope i dont have to change the starter motor again, with the manifold still on the car! what a barstard! oh and vice grips is what destroyed the nut in the end...

Yeah tell me about it. I've done about 5 or 6 of the dam things, starter motors that is. You've just gotta have the right amount of extensions and be good at contorsioning! If your lucky enough you can undo the top bolt with a 13 mm ring-open spanner, and if your even luckier you have a racket spanner like i do. lol