I tried to do a search for this but most of the posts are for the studs that go into the head. Both studs have stripped threads. I had to chisel the nuts off because they were basically disintegrated. We live in a real bad snow belt area. I bought the replacements, but can't get the originals out. Hoping there is a trick out there for removing these.

 

You could try an easy out or a left handed drill bit. Easy out you drill a hole in the center of the stud, drive in the easy out then back out the bolt. Easy. In theory. Becomes hard if you break off the easy out. Left handed drill bit you get one a little bit smaller than the actual hole in the manifold, drill it in the center with your drill in reverse, since that is forward for the drill bit, and hopefully at some point before you hit bottom it'll grab the stud and spin it out. If that don't work, you still have the easy out option.