Will a MIG weld stick to and/or mess up the cast iron? These are X heads that I planned on replacing with RHS heads this winter. I'm thinking I may make the swap sooner than that if I can't get this stud out on the car.

Thanks for the input guys. Keep them coming! I don't have access to a lather, but I like the idea of using the manifold as a guide. Just wish I had more room since I don't have a right angle drill... For now, I'm gonna let the steam dissipate from my head/ears for the next couple days..