The common conversion uses a 84-87 Toyota 4X4 steering box. Several aftermarket suppliers offer a kit which I believe is referred to as a 500 series box. It includes the steering box, pitman arm, drag link, steering shaft u-joint, and hardware. You will also need a pump w/brackets, hoses, pulleys & belt. I have installed several of them. ABS power Brake in Orange, CPP, and others sell the kits.
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