A 65 truck did not come with that steering box. It is a Saganaw power steering replacement from a later vehicle. It was probably a used part when it was installed and likely needs to be rebuilt or replaced. Also check for a worn idler arm, ball joints, tie rod ends, and A arm bushings. All contribute to sloppy steering.
Fred
It could be a kit from REZ Engineering. I think they may be out of business now, but their kit was a good one. Easy to install, and only needed to make two cuts, one to modify a corner of the bumper bracket, and the other to shorten the shaft. When I did mine, that truck along with a front sway bar, handled so much better, and could actually get out of its own way. Unlike the school bus steering it had prior to the upgrade. Of course, his could be just a cobbled-up modification using junkyard parts.