Yes, I have studied this as of recently, you can use the rear bearing cover (including speedometer drive and driven gear) of yours and install it on the later trans with your yoke, u-joint and torque tube adapter and you will be just fine.

I have 2 sm420 in my garage apart rebuilding them , one a 54 and the other a 60s and they are the same.

Last edited by sstock; 02/22/2018 11:31 PM.

1953 Chevrolet 3100
261 cu inch, sm420, 3.55 rear, torque tube still,omaha orange, still 6 volt, RPO green glass, side carrier spare, all done
In the DITY Gallery
Video of the 261 running

1964 GMC 1000
305 Big Block V6, sm420, the next cab off restoration