I asked why because there really isn't a good reason to change what you have if all it needs is rebuilt. Bushings, king pins, tie-rod ends, and rebuilding the steering box will make a big difference in how it drives. Change to modern tires and it will drive as good as anything on the road. Add disk brakes to what you have. Once you rebuild everything and drive the truck for a few years, then if you still don't like it, change the front.
