Just so there isn't more confusion. 55 is the only year with different shifter configurations between 6cyl and V8 trucks.
Any 56 through 59 3 speed and 3 speed OD transmission components with the 4 bolt side cover can be used. Those include the shifter box, rods, clamps, shifter arms, and side cover.
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