There are essentially three spring relocation kits on the market. Mopar makes one that pulls them in .75 per side. Dr Diff makes one that pulls them in 1" per side. Both of these utilize offset brackets and shackles. They also will require moving the springs perches on the axle housing in the corresponding amount, or another popular swap is to use a 68-70 B body rear housing whcih drops in to place on the new spring location. The third kit is the 3" per side pull in which requires cutting in to the frame rail and replacing it with the boxed section that then becomes the front hanger for the leaf spring.