Hy wurlitzer46, the 1/2 ton 1955 B or second series differential will swap into the torque tube housing. I believe the same differential was used up to 1962. Once you make your swap you will have to do something about keeping your new pinion in position as your torque tube housing will pivot on the rear springs allowing the pinion to fall down. You could have someone weld leaf spring mounts to your housing and you will have to obtain some "U" bolts and plates to bolt the housing to the springs. Don't forget the pinion angle needs to be set before the welding, hope that helps.
