Hy jim72051 I don't believe that any of the fifties frames will be an easy swap to your 46. the early 50s frame would be the best choice if you want to try, if my info is correct there is a wheelbase difference of 1" between the two frames. The 40s frames are tappered from back to front, as are the early 50s frames, the post 55A frames are rectangles, and lots of adapting would have to be done. As to 1/2 versus 3/4 ton there will be wheelbase differences, and heavier components to deal with, hope that helps.
