Unknown Backing Plate form an 8"

A buddy of mine (non computer needs your help).He has an 8"Ford rear end he is putting in a Model A 2 door sedan. He has a damaged backing plate he wants to replace, but doesn't know what the rear end came from. The holes in the backing plate are most unusual.With the drum off and the backing plate removed from the housing here's what it looks like. The backing plate is 10" in diameter.
The large hole in the centre is 2-11/16" in diameter. Now here's where it is different. The four holes that hold the backing plate on are
not spaced the same. The top two are 3-1/4" inches apart. The bottom two are 2-7/8" apart. The vertical distance between the top
row of holes and the bottom row of holes is 1-11/16". Can anyone
help identify this rear end? What did it come from? If we can ID the rear end it will sure make it a whole lot easier to find a backing plate.
If anyone has a backing plate like he needs and they want to sell it let me know ............ Thanks for any help Dave

 

Could it be a Mustang II rear end ?

I believe they have a different housing end to the earlier 8 inch rears.

They are originally 4-stud axles, but there are 5-stud axles that can be swapped in.

 

It has 5 stud axles ,any help? Dave