I'm not sure what number designator was used for the 47-54 torque tube type transmission. SM318 is the common term used for the 55-67 4 bolt side cover transmission used with an open driveline. There is a long and short tail housing version.
The internal components are different with the possible exception of the clutch gear. If you are going to buy gears or another trans it would be better to specify the year so you don't end up with a bunch of stuff you can't use.
Fred
