If it is the stock trans out of a 56, it will be a SM-420 4spd with the 7.1 to 1 1st gear. This trans was used from 47 to 67 in the 1/2t to 2 1/2 ton model trucks. Hope this helps, Garry


Garry K in Pac Nor West
1948 Chevy PU 235 SM420 4 spd
1932 **** B pu
1964 Datsun 4x4 with SBC, SM465 4spd and Rockwell xfer Dana 44Fr and 12 Bolt Rr.