I am in the process of doing my king pins on a 1950 pickup. I did not need heat. Just take off the backing plates, have the frame on stands. Remove the soft plug at top of king pin by drilling a small hole in it, then use a wedge to pry out. Then place a bottle jack under the king pin. Start jacking up, using a bolt smaller than the size of the bushing. After raising an inch, bang on the top of the axle with a huge hammer. The king pin will gradually start coming out the top. New kit from Filling Station in Oregon has all you need. Add grease and install.
