Here is my 9" rear end I'm using:







Thanks guys!!!

 

Casting numbers on Ford parts are meaningless. You need to go by housing shape, pumpkin shape, wheel flange to wheel flange length, bolt pattern, etc to ID. According to the tag it is a 3.70 ratio. Not a bad ratio (same as I'm using) for short drives with a small engine with non OD tranny, towing, carrying loads. With today's fuel costs you might want to consider a higher ratio (numerically smaller like 3.5 or 3.23) or an OD tranny if doing distance driving or daily driver. I am using a T56 6 speed std which has OD 5th and 6th for the best of both worlds accelleration and economy.

here's info on rear axles: https://www.ford-trucks.com/article/...ial_Swaps.html

 

Per the tag it is a non traction lok diff. (Not posi)

 

If you google the "WDM-U 8LC" you can find what it's from, here's the best result from:
Ford Rear Axle Assembly Identification - Page 04 - FORDification.com

 

Thanks guys! Ross, that was what I was looking for....