cbob,
A 54 truck has a closed driveline (AKA torque tube). It is not going to match up with any of the later
5 speed or any open driveline transmissions. If your truck is actually a 55 first series, it would have an open driveline.
Otherwise you will need a complete rear end, driveshaft, and modify the rear spring/housing mounting configuration.
Fred


1956 3100 Pickup/Red/350/3sp OD/PS/Disc Brakes
1957 Bel Air Sport Coupe/Red/355/TH350/PS/Disc Brakes
2017 Silverado LT Single Cab SB/Black/5.3/6 Speed Trans
1947 Willys CJ2A w/F-Head engine