Tag: SM420

Dear Welder Series… GM SM420 Transmission Mount?

Dear Welder Series…
I ordered universal motor mounts an the tranny kit. The motor mounts will work fine. The tranny kit baffles me at this point. It is a beautiful design, and I would like to use it as it will give me plenty of clearance for dual exhaust.
The tranny is a SM420 that GM used from 1947 to 1967. It is a 4 speed manual with the lowest 1st gear ever. Pretty popular with Jeep people these days. The tranny mounts at the bell housing.

I noticed on the web that many 4 wheelers have transfer cases attached the would mount from the back. This is going into a 1962 Dodge d100 truck. 2 wheel drive (no transfer case).

Let me know if you have any suggestions.

Spoke with Paul yesterday


Dear Rick…
Rick, it looks like a crossmember will have to be fabricated with tabs or bosses to line up with the holes in the transmission.  Urethane bushings could be used at each end of the crossmember to provide some insulation.  Brackets welded to the frame would put the urethane bushing in double shear.

I hope this helps feed your imagination.

Paul Horton