I'm still in favor of my earlier suggestion of disconnecting the torque tube at the ball joint, raise the front end of the torque tube upward til it touches the flooring panel.
It is a 3/4 ton, so the driveshaft is made up of an conventional external shaft with 2 u-joints coming forward from the differential and connecting to an enclosed shaft at a center hanger. Here is the picture from the GMC parts book.
'57 GMC 102, Original 347 V8, HydraMatic, 3.08 rear gear, added A/C, disk front brakes, HEI, AFB carb, '98 Honda Black Currant paint. T-boned and totaled 10/12 '52 GMC 152 Stake Bed, Original 228, SM420, added A/C, HEI, disk front brakes, '67 Chev 3.55 rear gear. Gets used as a real truck.
