Upgrading Rear End

You'll need 3in u-bolts, you can slot the holes on the shock mount pads to accept the larger u-bolts. Are leaf springs sagging? If so they need to be replaced. Install new axle and have weight on wheels, install yoke all the way, pull yoke out 1.25 inch, measure center to center of transmission yoke to pinion yoke. Have someone help you with the measuring. If the axle has a 7290 yoke, there are conversion u-joints, Precision U Joints makes them and you can get/order those at. Any auto parts store. Remember, measure twice, cut once.