These are the two most common Axle Ratios used by Ford in the Six powered cars that you will find in these 7 1/4 Inch Rear Axle Differentials. The 2.83 to 1 that was standard stock Ratio in all of the Auto Transmission Cars as well as the Ranchero's and Sedan Delivery's. The other common one was the 3.20 to 1 that was the standard stock Ratio used in most the 3 Speed Manual Trans Cars as well as the Ranchero's and Sedan Delivery's or as a special order for an Auto Trans. There were also two other optional Rear Axel Ratio's used in some of the Manual Transmission Cars or maybe as a special order with an Auto Trans, the very rare 3.50 to 1 Ratio and then also the 4.00 to 1 Ratio option these were most often put into the Ranchero, Station Wagon's, and Sedan Delivery's with a Manual Trans that were used for more heavy duty type work or Deliveries and also some that were used in Military Vehicles. There was also a Limited Slip Axel option that you could order and sometimes you can still find them, the Chrysler small Cars (Valant, Dart, etc. also used these Limited Slip Axel Differentials in their Lighter Duty Axel's and these can be swapped into the Ford 7 1/4 inch Axels too. Most all of the Bearings, Seals, and Gaskets are still available new to rebuild them. Good luck in the hunt.
