[Rick Parker]

History Lesson:
The 9" diff was a rare piece in the Granada/Monarch 75 (?)-78, they primarily used the 8" diff. The 9" differential was primarily found oddly enough in 6 cyl Taxi cabs. During its production run the Granada was exceedingly popular as a Taxi and Ford equipped consequently them with reasonably good brakes and the larger rear axle assembly. The consant loads and stop & go fared better with the disc brakes & the larger diff. The narrow 9" was standard with the disc brakes in the more upscale 77-79 Lincoln Versalle. In '79 or 80 (?) the rebodied Granada shared their platform with the also restyled and first generation "Fox platform/chassis" from the '79 Mustang. I don't think any of the Fox chassis had 9" diffs as an available option regardless of their intended usage.
Don't be afraid to take a wider housing and narrow it down. If you ARE able to find a Versaille rear, you will normally pay a premium and also pay a higher than normal price for calipers (VERY HEAVY) and the like.