My recommendation is to get one and everything will take care of itself. These OD units are the best kept secret for the older trucks. I have built and installed dozens of them over the last 30 years. Parts are still available you just have to root them out. I just set one up this week using electrical components available from Napa.
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