Most Mfg used a BW OD in conjunction with their own OEM transmissions. Many of the internal OD parts will interchange with other mfg OD units but the basic transmissions are different. Rambler used a torque tube into the mid 60's so as far as I know nothing from them would fit your truck.
What you should look for is a Chevy OD trans from 55-65 car or truck and /or a 66-69 OD which is a full syncro.
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