Rearend Housing 3″ Tube Spring Seats. These have a 5/8″ Center Locating Hole. On the Factory Leaf Springs you will need to Turn the Locating Pin/Bolt around, as these are made to fit the Nut side of the Pin/Bolt instead of the 1/2″ Locating Pin they have. On some of the Aftermarket/Reproduction Leaf Srings, they will already have the Locating Pin/Bolt with the Nut at the Top for these to fit over. You may have to Cut some of the Bolt Threaded End down to just above the Nut to keep it from Bottoming out into the Axle Housing Tube for it to Seat properly.