oldblu49 has it right, assuming that Jim G's truck is a '49 3100 (1/2 ton). If the truck has an open driveshaft, then the transmission, driveshaft, and rear end are not original. However, that combination might have gearing that will give you better hiway driving.
1947 was the last year that the three-speed transmission used floor shift, and the last year that the 1/2 ton parking brake was activated by a lever next to the floor-shifter. After-market floor shifter adapters were available for many 3-speed transmissions (I remember them in JC Whitney catalogs).
Tim
