8.1 Workhorse exhaust bolt broken

You can buy left fluted drill bits that do their cutting on reverse. While it's drilling the bolt will loose it's strength and spin out with the drill bit. One thing to think about is if it breaks again and leaks long enough, the hot exhaust can start to burn a channel at the head. At that point, you can't seal it with anything. If you google "broken exhaust manifold bolt" there are many good examples of ways to do it. I like this way myself.

Tig method