So I decided to swap out my exhaust manifold studs and nuts and gaskets due to a minor leak. I had a buddy of mine over at the time so he was helping out with the simple project. I finished tightening my side issue free and passed of the torque wrench so he tighten up the 3 nuts on his side, and on the very last one he says, "hrmmm, something seems off on this last one." Sure enough, the stud just falls right out when I look at it with stripped aluminum on the threads. Fuck you Murphy. Whats the best way to repair this?