The big thing in a 9" is the bearing at the nose of the pinion gear.. it controls the pinion deflection and the 8 3/4 doesnt have it.. the pinion tends to deflect and breaks the teeth off... on the back brace.. both are sheet metal housings and will bend.. the back brace is needed on both.. on a leaf spring car it bends front the spring pads outward so you need the brace going to the ends
My understanding is the pinion tries to walk up the ring gear. If I were to use the 8 3/4 or a DANA it would probably be just fine. But the amount of work on the 8 3/4 to make it work is the same as the 9. But the 9 has a stronger AFTERMARKET design. So I'm still left with the weak link 8 3/4, the teeth.
You guys can run what you want. Some get away with it some don't. The 9 works for me so that what I'm going to use.
