Mechanic joint have the flat area with 4 bolts to mount the rear joint of the drive shaft, i think that is what you are meaning with stepped ledge whereas the later drive shafts had U clamps.

marv

Forgot to mention, it did have the Mechanics style yoke on it with a 10 spline pinion.  I didn't find history of it going back into the "flattie" era.

By mechanics joint do you mean the caps with the stepped ledge in them? Chuck

Y's guys rule!
Looking for McCullouch VS57 brackets and parts. Also looking for 28 Chrysler series 72 parts. And early Hemi parts.

MoonShadow, 292 w/McCulloch, 28 Chrysler Roadster, 354 Hemi)
Manchester, New Hampshire

If the rear end has the regular style of U-joint instead of the mechanics joint it could be the differential that was used on the late 1956 312 cars. They are rated near as tough as the 57 differential.This was a predecessor to the 9 inch used in 1957. (57's were not true 9" differential either)

marv

I've never found a diameter specification or nickname for those rear ends. They were used in Ford cars from 49 to 56 but not in T-Birds or Station wagons. I even found a "Detroit Gears" posi unit for mine a few years back. Chuck

Y's guys rule!
Looking for McCullouch VS57 brackets and parts. Also looking for 28 Chrysler series 72 parts. And early Hemi parts.

MoonShadow, 292 w/McCulloch, 28 Chrysler Roadster, 354 Hemi)
Manchester, New Hampshire

Had a guy come in with a rear end needing complete rebuild for a "tribute" T bucket.  He thought he had a 9".  I looked at it and said no, not even an 8".  Was convinced it wasn't even Ford until I took it apart and found the oval and part numbers on the ring.  After a week of chasing part numbers, found it was used on some 56 only cars, but not wagons or T birds.  Believe it or not found every bearing and seal except the pinion seal which I had to do by sizes, and had to "manufacture" a spacer/ shim kit to set the pinion preload.  This must be the predicessor to the 9" in 57? as it seemed pretty light duty.  A completely new one on me and thought it might have some serious value for a restorer.  Anyone else ever come across this or did I just forget my history?