1967 Ford Mustang mileage: 77000.I have a question on how to tell the difference between an eight inch and a nine inch rear end. The tag is missing and the stamp on the differential is C70W 4025A 9. The spaces represent a new line on the differential. Any info would really be appreciated.
The most sure fire way to verify the size is to disassemble the differential and measure the diameter of the ring gear. Most Ford Mustangs with the 289 had eight inch rear ends. Most Mercury Cougars of about the same year had the nine inch rear ends.