The Ford 9 inch rear end is one of the most popular axles in automotive history.
Ford’s 9 inch rear axle was produced from 1957 through 1986 and was installed in nearly every Ford passenger car and truck at one time or another. It was then replaced by the Ford 8.8 inch rear axle.
Hot rodders and drag racers use 9″ Ford rear-ends and their aftermarket descendants in just about everything — not just Ford cars and trucks. Many aftermarket companies produce 9″ Ford equivalent rear axles for the drag racing and hot rod industry.
The Ford 9 inch housing is a semi-floating, drop-out axle. Because of their strength, you’ll see these 9 inch rear ends used in just about every make of car, truck, and customs.
Ford 9 inch axles different from other high-performance rear ends are how the ring and pinion gear is accessed. It allows for the pinion side “Center Section” to be removed.
The center section is the differential assembly. This includes the Center Case, the Pinion gear, the ring gear, and the differential or spool. This is a major advantage compared to other rear axle systems because disassembly is faster and more convenient.
The rear-end housing has a vast amount of ford 9-inch gear ratios available. This combined with easy assembly makes it popular for fine-tuning a rear gear for any particular application.
Common Vehicles with Ford 9 Inch Rear Axles
- 1967-1973 medium and big block Mustang and Cougar
- 1966-1971 Fairlane, Torino, Montego, Comet, and other Fords with big-block engines
- 1957-1959 V8 Fords and Mercurys
- 1977-1981 Lincoln Versailles and Trucks
Ford 9 Inch Rear End Widths and Potential Donors
|Axle Width||Year Model||Notes|
|56.50||1974 Maverick 8″ Rear-end||8″ Rear-end but Narrower Alternative|
|57.00||1975 Mustang II 8″ Rear-end||8″ Rear-end but Narrower Alternative|
|57.25||1957-1959 Ranchero, Station Wagon||Narrowest 9″ Housing|
|58.00||1966-1977 Bronco||5×5.5 Bolt Pattern|
|59.25||1967-1970 Mustang, Fairlane, Comet, Cougar|
|59.25||1967-1971 Comet, Cougar, Mustang, Fairlane|
|59.25, 61.25||1967-1973 Torino, Ranchero, Fairlane|
|59.25, 61.25||1967-1973 Mustang, Torino, Ranchero, Fairlane|
|61.00||1964-1971 Ford Full Size|
|61.25||1957-1972 Ford F-100 Pickup|
|61.25||1960-1964 Ford Full Size|
|61.25||1967-1973 Torino, Ranchero, Fairlane|
|63.00||1970-1979 Ranchero & Torino|
|63.00||1972-1979 Ford Full Size & Intermediate|
|63.50||1967 Fairlane||Coil Springs|
|65.25||1973-1986 Ford F-150 Pickup|
|65.25||1973-1986 Ford Van 3/4 ton|
|68.00||1972 Ford Van 3/4 ton||Widest 9″ Housing|
|69.25||1977-1986 Ford E-150 Van|
Ford 9″ Rear-end Housing Construction
- 1967-1973 Mustang/Cougar
Light-duty, thinnest housing material, small axle bearings, 28 and 31 splines.
- 1957-1968 passenger car and 1/2 ton truck
Medium-duty, stronger than Mustang type, 28 and 31 splines.
Heavy-duty thick wall housing, 3.25-inch diameter axle tubes with flat tops.
- 1969-1977 Galaxie (coils), Lincoln (coils), and late pickups (leaf)
3.25-inch diameter all the way to the backing plate, coil housings have upper control arm mount
How To Identify 9 Inch Ford Housings
- 1957 – no dimples, flat center band up the center of the rear cover, bottom drain plug.
- 1958-1959 – two dimples on the back of housing, flat center band, some had drain holes.
- 1960-1967 – two dimples, flat center band, oil level hole in the back cover.
- 1963-1977 Lincoln, LTD, Thunderbirds had 9.375-inch centers, housings were cut away at the gasket surface for ring gear clearance, one curved rib at the front top portion of differential, strong but no gears.
Shortening Ford 9 Inch Axles
- 1972 and earlier, 31 spline axles have the ability to be shortened.
- 28 spline axles are tapered and cannot be shortened and re-splined.
- 1973 and later cars have a 5×5 bolt pattern, and the axles cannot be shortened.
- 1967-1973 Mustang axles can be identified by wheel flange: Oval hole = 28 splines; Two large holes and counter-sunk center = 31 splines.