When I got the truck it had the 3 speed floor shift which I know was not available in 1953, but the engine is out of a 1955 Chevy so maybe the 3 speed is from 1955 ?
I will be overhauling the tranny this winter and then will find out exactly what I have.

1953 chevy 1/2 ton with 3 speed 318 on floor and 1955 235 engine