The Craigslist transmission is a 1955. It has the governor and solenoid.
Missing are the pull cable, relay, wiring harness, carburetor bracket and kick down switch.
The 3 speed gears are common with non-overdrive transmission gears.
The Borg Warner tail housing (R10H-1) if worn or damaged, can be hard to find repair parts.
Unless you live locally, shipping can be a bit expensive.

"Adding CFM to a truck will only help at engine speeds you don't want to use."
"I found there was nothing to gain beyond 400 CFM."