The manual steering box is still used on that system, with a push-pull pilot valve incorporated into the boost cylinder to direct fluid to opposite ends of the cylinder ram as the Pitman arm moves. It was a stock setup on some trucks, but the parts are scarce and pricey now. The weak link is the hoses- - - -they flex constantly and spring leaks pretty often. If you can find a salvage yard truck with the P/S system intact, grab it all, and adapt it to your truck. Challenging, but doable for someone with fabrication skills. Just be sure and build the frame brackets twice as strong as you think they need to be. Heavy loads and pothles in the road combine to put some nasty stresses on steering linkage.
Jerry
