The torch approach hasn’t worked for me in the past. I found that drilling into the perimeter of the busing 8-12 times (1/8-3/16” bit), then finding a metal rod about the size of the bushing and beating the crap out of it with a 5lb hammer did the trick. Might have to cut off the flange portion of the bushing first. I think I used a 4” cutoff wheel or dremel for that. All told it took me maybe 10 minutes per pair of bushings.
I'm guessing you are referring to the old bushing in the frame? The torch works but its messy and the smoke is probably about the worst thing in the world you can breathe so be sure its a well ventilated space and dont breathe. Those bushings usually have a steel inner sleave for the bolt to pass through, a rubber bushing which is cast into a metal outer sleeve. Sometimes you can heat the inner sleeve with a torch and then push it out of the rubber. Then you can take a sawzall and cut the rubber in several places and rip it out. Then you can carefully cut through the outer steel tube of the bushing...once you have a cut in it you can use a small chisel or screw driver you dont like and a hammer to bend the metal sleeve inwards....eventually you can usually free it and pull it out. Sometimes they are thoroughly rusted in and it can require a fair amount of cutting and prying to get them out