I put the truck box in my '57 Ranchero, and it is not a simple swap. I had to weld an ear to the box for one of the mounting bolts, and had to drill and tap for another one. A modified pitman arm was required, and the steering column cut off just inside the firewall, a bushing fabricated to press in the tube to support and center the shaft, and a "rag joint" adapted to the shaft. A standard steering drag link was used. An inside the firewall support had to be fabricated to mount on the column tube and support the shift linkage. Also, with the rag joint and the non hollow shaft into the box, the original horn ground wire was history, requiring more fabrication and the use of a fork lift horn brush to make it work. And then there was the hand fabricated cover to make room for the rag joint and shift linkage to cover the hole in the firewall and toe board. I used the original Y block pump with specially made hoses. Good luck if you pursue this direction.
Re your play and clunk, has anyone checked to be sure the steering box is still tight to the frame? Vertical movement in the idler arm can cause play also.
John - "The Hoosier Hurricane"
