You can change the pump pressure by installing additional washers in the pump control valve. This is a common practice when using a GM pump with a Ford rack or a Toyota PS conversion which run on less pressure. This is likely not your problem in this instance. A GM pump and Saganaw steering box are compatable so you probably don't have a pressure problem. There are several steering boxes available, some of which have a very fast ratio. They are generally used in Camaro's and other performance vehicles. The fast ratio boxes have about 2 1/2 turns lock to lock. This ratio is probably to fast for your truck and may give you the symtoms that you have described.
Fred
