Maybe the more tenured in this crowd can answer a question for me? Why is a 9" so much stronger than an 8 3/4"? Many talk about back bracing 8 3/4" rears and someone always says that it is a waste of time yet, to do it on a 9" is okay and not a waste.
For the most part, the two designs are very similar so; why is the 9" so much stronger? Couldn't you just do the same modifications to an 8 3/4" and have a similar result?
You back brace the housing to strengthen the housing itself, to keep it from bending. This does ZERO to strengthen the 3rd member, which is the weakness of the 8.75. Guys say they are going to backbrace their 8.75 in attempt to FIX the weakness of the rear. Does NOT help.
The ONLY similarity between a 9" Ford and an 8.75 is that they are front loaders, other than that, they have ZERO similarities. The pinion assy in the 9" is contained in a removable cone and the case has a bearing that supports the nose of the pinion, therefore fully supporting the pinion on both ends. THIS is what makes the 9" design WAY stronger than the 8.75. Pinion deflection is what kills 8.75s. It can NOT be fixed. It happens in high power applications and there isn't a thing that can be done about it. There are band aids that supposedly help, but not really. It WILL break eventually. The 9" Ford, with it's fully supported pinion is the best front loading designed center, which is the reason the aftermarket chose it to concentrate on. There is absolutely NOTHING wrong with the factory design, but in high HP apps, you need a front support made of better metal. Some argue the lower position of the pinion takes more power to turn but that hasn't proven to amount to anything on the race track
Makes sense.
Thank you and the others above for answering my question!
