There are numerous side covers and different clock positions for the levers depending on the year, model, and if it is from a car or a truck. That doesn't change the 2-3/1-R locations. It is quite common to have to use your existing side cover when making the switch. That series Chevy overdrive is an SM319.
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