6.1 Hemi Internals.

I'll throw something out there for everyone to ponder. I'm sure not everyone has been up close and personal with a locomotive engine, so I'll explain. In particular, GE loco engines use huge head studs as you can imagine. They have a tool that stretches the stud and you simply run the nut down to a very minimal torque, practically hand tight. Then the stretching tool is released and now the head is torqued down. These studs aren't one time use. Perhaps the argument could be the stress isn't being put onto the thread while the nut is being tightened down, but at the end of the day its still stretching the bolt.

There have been plenty of people reuse head bolts on LS engines with tons of boost without problem. It all gets down to personal opinion. If you are building a car for tons of power, chances are you aren't using factory replacement head bolts.
Yield, by definition, means the part has been permanently deformed.
I don't particularly agree with this. If the threads on the bolt are permanently deformed, they would tear the threads on the block on the way out.