Pull the output yoke off the back of the main shaft, the drive gear is pressed on that. Course you will have to remove the ujoint to get to it. Might be better to go to your local speedometer shop and have them install an adaptor like truckfarm said, drive and driven gears are getting hard to find for the sm trans plus it would be cheaper in the long run Dave.

Last edited by sstock; 03/23/2018 8:25 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