"So you’re using just the ‘57 pumpkin and drive shaft, and retaining the original differential housing and axles, is that correct……to eliminate the torque tube. Correct??"
Correct, except for the drive shaft. You are now entering the world of custom made or modified driveshafts (length).
Klhansen is correct about setting the driveline angle and welding the pivots solid, except I don't believe the pivots on your 46 contain rubber. No mess, set the angle and weld.
