9 inch gear fitment....

Did some searching but came up empty. I plan on changing gears in my first ford nine inch diff, 3:08 to 3:89. Do all the ring and pinions fit all the different year pumpkins, 57-80 ? GM has the different series ect, anything to watch for with the ford 9? Thanks allot!

 

Third members interchange, but the early ring gears (1957 and possibly '58 and '59 ) were not quite 9" diameter and the earlier housings have to be notched at the gasket surface area before a later 3rd member with an actual 9" dia ring gear can be installed.
Unlike a Chevrolet 12 bolt, a Ford 9" uses the same size carrier for all ratios, and the thickness of the ring gear varies (basically, the thicker the ring gear, the lower the ratio).

 

Ring gear face is same on all spools/differentials. A housing that had high gears (low number ratio) will not have been clearanced near the third pinion bearing. Newer gears are trimmed on the inside and have more clearance, but you still need to make sure it has clearance. The steel gear will clearance itself as the housing is cast, but that is not the right way to gain that clearance.

 

Of the Ford OE variations I've witnessed of a 9" Ford housing, the only odd thing to me is the larger OD pinion seal of the very first generation pinion support housings. They used a seal that had a larger OD than a National 7044NA seal.
After that, the common differences like, full ribs vs later, nodular N case designation, Ford small and large carrier bearing inside and outside diameters, 28 or 31 spline axles, small axle bearings RW207CCRA, large axle bearings 514003 or 88128RA, later axle tapered bearing A20 w/3195 seal to the outside of the bearing. Some carrier housings have fill plugs while the axle housing doesn't and the opposite.
Standard 2 pinion carrier housing, standard 4 pinion carrier housing, Trac Loc housing, Detroit Locker installed from the factory.
That excludes aftermarket variations that haven't been described. NO parts books opened yet, just memory. Other variables about axle housing ends and etc.........