Join Date: Sep 2001
Location: Milwaukee (Sussex), WI
8" & 9" refers to the ring gears within the center section of the rear end. Those gears themselves are not interchangeable. You need to replace the entire rear end housing, basically from wheel to wheel, including the center section. 9" rear ends are very popular for their strength, but likely overkill.
Chris (Sussex, WI)
289 w/AFR 165, T-5z, 3.55T-loc, Granada Discs and 6 bolt Moto-Lita Steering Wheel