A 9" would not shear pins or break carriers. It's used for drag racing. Even people with Chevy's use the Ford 9". I have one, and it's done more than the 8.8 could handle. The 9" pinion grabs more of the ring gear than the 8.8 does.

 

Being a Ford partsguy by trade (I was, for 35 years), you are prolly aware of the following:

I was sorta correct, cuz D8BZ-4241-A was replaced by D8BZ-4241-B due to a package quantity change in the late 1980's.

When FoMoCo made those gazillions of package quantity changes, the idiots changed the part numbers suffixes, rendering all the previous numbers obsolete.

Since this occurred after the last printing of the 1973/79 car/truck parts catalogs, none have the new numbers. If the partsguy is aware, the O-S-I catalog is required. If he ain't, the customer is prolly SOL!

The most flagrant example IMO was D0TZ-7B097-A which was replaced by B. When still available, some peeps were being told that the part was obsolete. Today, peeps are still looking for the A suffix.

D0TZ-7B097-B (replaced D0TZ-7B097-A & C5TZ-7B097-A) .. NSS Selector Lever / 1965/77 F100/350. This is one a the most frequent part numbers I've typed on FTE, cuz the part is a POS.