It should be a direct bolt-in as far as the spring pads and u bolts size, (I would use new u bolts). The problem may be in where the brake line junction block is bolted to the 9in. compaired to the 8in. You may also have to change the rear universal joints to match the 9in yoke. Don't forget about the emergency brake cables.
well sounds like more than I'm ready for right now, I just want to get moving again until I can put a Currie back there...Then I'll beef the engine way up. My goal is to run 450hp I'm presently running a 302 W/Ported GT40 Heads, Edelbrock Intake, 650 Holley, HEI Distributor, K&N Intake, Ford Racing shorty headers, 3G alternator,Dyno says I'm running a little under 300rwhp I think it's because my gears suck.