Not being a ford guy and this being my first rebuild project Im trying to figure out the rear end and differential.
There is no tag on it. On the housing I found c70w 4025-a 7 and on the ring it self I found ford usa c60w 4210a 3-04c
What do I have???
Looks like it was removed from a '67 Fairlane or Torino (3rd char=O for Fairlane and early Torino)(4th char=W for Rear Differential part), that is as far as I can get with those casting codes. Which means your door codes will not tell you what it is, but maybe the ratio was matched if your lucky. Just see how many times the wheel goes around for one rev of the driveline.
Or count the teeth. # ring gear teeth (divided by) # pinion teeth = ratio
Ring Gear should be stamped with the ratio !
If you have to use a wrench on the bottom most nut of the housing carrier nuts, you have a 9". If you can get a socket straight on the bottom nut, you have a 8".