I did a big bearing 9" in mine because I couldn't find an 8 3/4 around here in the bolt pattern that I needed. I did already have the 9" for another project. I narrowed it myself, ordered custom axles, detroit locker and 3.89 gears. I even installed rear disc brakes from a explorer with an 8.8 axle for $40 (with minor mods). A 9" is very easy to work on, like the 8 3/4, but the furd has a ton more gear options.