So close to running, but then this happened!

I was dealing with the same thing when I put my headers on, but it was already broken off.
It is the one on the drivers side rear, and was a PITA to get to, plus it was broken off flush with the head.
I put a nut over it and filled it in with a gas mig welder 3 times but it just twisted off again. (even heating and soaking with WD40)
I drilled it and used an easy out, and that snapped off in the hole.

I plan on changing the heads anyway and used Remflex gaskets, so I just went ahead and put it together and going on a year and no leaks.
Remflex says no re tightening needed with their gaskets and guarantee no leaks, so I figured I would just see how good they are.
After a day or so of running I went back a checked all the bolts and they were still all nice and snug.
A week later I checked them again and they were still just as snug.
I will NEVER use any other gaskets for headers again.