It'll either be a nine inch or the 8.7 inch (yup, they really made one). Of course it'll have 2.75 or 3.07 gears in it. And way too wide.
So the 8.7 inch is a Dana 44? Now that I didn't know. Thought they only used those in trucks and Bronco's. My 75 had that axle with a 3.07 ratio. Thanks Baddad.
I bought a 72 LTD a few years ago and the rear was a Dana 44. As for whether it's the same thing as the 8.7 you're talking about, that I can't tell.
Yeah, mine was the WER axle. Guess it might have been Ford's own design. I see the Dana 44 was a 8.5 inch gear. I still haven't figured out if the "New Design" 8.5 rear that came out in 79 metamorphed into the 8.8 of today. They seem the same, but you never know.
Yea, more'n likely was the direct ancester to the 8.8. 8.8" is just the nominal ring gear size anyway, the actual measurement is likely different between ratios. I know they are in the 9" rears. The 9-3/8" rear used the same basic housing as the 9" did. Just had a different chunk. I do remember being surprised to find that Dana 44 where I was positive it would have had a 9" rear.