It would seem as though the longer part of the 3 speed yoke is the end into the trans. That will not help you. Just a thought on the frame........is it possible it is indeed a half ton frame, but from a GMC? They are just a touch longer.
1947.2 GMC 1/2T SWB panel 1947.2 GMC 1/2T long bed 1948 GMC 1/2T short bed