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)
California car born an I6, now with warmed up 289 w/T-5z, 3.55T-loc, Granada Discs and 6 bolt Moto-Lita Steering Wheel. Owned since 1983.