Thank you!!
 

I had what I thought was a missing bolt in my DS cylinder head (see photo). I tried to put a bolt in the hole and thought a bolt was broken off inside. I then read a post suggesting welding a nut to the broken off bolt. Once I removed the alternator bracket I could see a small piece sticking out of the head. I bought a 3/8" nut and MIG welded it to the piece sticking out and the piece threaded out with very little effort. The piece turned out to be the end of a 3/8"/16 tap. Someone broke a chase tap off and left it in the head.

Thanks for the EXCELLENT advice, it worked great!