To set up a 9" correctly, you need a dial indicator and the fixture to measure the pinion depth, along with the knowledge of how to correctly set the backlash..... Mike is correct in saying that you would be better off to hire someone experienced with setting up gears to get it done right. Years ago I bought a complete set up kit from Speedway, think back then it was $150.00 or so. Along with the new ring and pinion you'll need an install kit (bearings, crush sleeve, etc) to go with it.