I would reconsider using the factory type bushings for your springs and shackles. The originals lasted for many years. Save your money for other parts.
My concern with the shackles is that they are held on and in place with the center bolt and nothing else. That and the fact that it's always metal on metal. They certainly did last a long time but having taken apart the truck and having had to replace all the shackles and the bushings - there really is no way that poly bushings like those used in off road equipment is not the way to go.
