One of them came out easy with ViseGrips after a few cycles of the propane torch and PB Blaster. The other one took some more effort. After the above attempts failed I screwed on a nut, half it’s thickness down on the bolt so there would be a reservoir to weld into. Then I welded on a nut and while it was red hot I used a can of Freeze Mist to chill and contract the bolt. Then an impact wrench got it off the first time.