Chevr aulait,

The u-joints from '47.5-'54 are the same for three speed transmissions (4 speed u-joints are different from the 3-speed but are the same from '47.5-'54).

The '53 and '54 standard commercial 3-speed have a few different internal parts from earlier years but the splines on the rear of the main shaft are the same for all years.

Tim