1957 to 1986 Ford rear end widths
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Original credit to Dave_C and the Fordnatics mailing list - original data from https://mustangsandmore.com/ubb/FordRearDimensions.html
This list provides flange-to-flange measurements for Ford rear ends.
Not sure which rear end you have? The code on its axle tag gives the ring gear size, ratio and splines: look it up in the Ford rear axle tag guide.
Note: These measurements are from flange to flange. Subtract 5" for bare housing length.
Axle Width Reference (Flange to Flange)
| Vehicle Application | Width (Inches) | Notes |
|---|---|---|
| 57-59 Ranchero & Station Wagon | 57.25" | Narrowest 9" housing |
| 64 Falcon | 58.00" | |
| 65-66 Mustang | 57.25" | |
| 66-77 Bronco (9") | 58.00" | 5-on-5 1/2" bolt circle |
| 67 Cougar | 60.00" | |
| 67 Fairlane | 63.50" | |
| 67-70 Mustang | 59.25" | |
| 67-71 Comet, Cougar, Mustang, Fairlane | 59.25" | |
| 67-73 Mustang, Torino, Ranchero, Fairlane (9") | 59.25" - 61.25" | |
| 71-73 Mustang | 61.25" | |
| 72 Ford Van (3/4 ton) | 68.00" | |
| 73-86 Ford Trucks | 65.25" | |
| 74 Maverick (8") | 56.50" | |
| 75 Mustang II (8") | 57.00" | |
| 77-81 Granada/Versailles | 58.00" | |
| 77-81 Versailles | 58.50" |
Mustang Rear End Widths by Year
Flange-to-flange widths for Mustangs, taken from the table above. Where the table lists more than one width for the same years, both are shown.
For the ratio and ring gear size a Mustang left the factory with, find its tag in the Mustang axle tag codes. If the tag is gone, the axle code on a 1964½–1973 Mustang's door data plate still gives the original ratio: look it up in the Mustang data plate decoder.
| Mustang Years | Width (Flange to Flange) | Listed in the Table Above As |
|---|---|---|
| 1965-1966 | 57.25" | 65-66 Mustang |
| 1967-1970 | 59.25" | 67-70 Mustang; 67-71 Comet, Cougar, Mustang, Fairlane |
| 1967-1973 (9") | 59.25" - 61.25" | 67-73 Mustang, Torino, Ranchero, Fairlane (9") |
| 1971 | 59.25" or 61.25" | 67-71 Comet, Cougar, Mustang, Fairlane; 71-73 Mustang |
| 1972-1973 | 61.25" | 71-73 Mustang |
| 1975 Mustang II | 57.00" (8") | 75 Mustang II (8") |
Lincoln Versailles Rear End Width
The table lists two widths for the 77-81 Versailles:
- 58.00": listed as 77-81 Granada/Versailles
- 58.50": listed as 77-81 Versailles
The 77-81 Lincoln Versailles is also listed below as a source of the Ford 9" rear axle.
The Ford 9" Rear Axle
Where to Find Them
- 67-73 Mustangs & Cougars: Medium and big block models.
- 66-71 Intermediates: Fairlanes, Torinos, Montegos, Comets (with big blocks).
- 57-59 Full Size: V8 Fords and Mercurys.
- 77-81 Models: Lincoln Versailles and various Trucks.
To check a 9" by its tag, the axle tag guide lists every 9" car axle tag from 1963 to 1980 with its ratio, splines and original cars.
Housing Types
- Light Duty: (67-73 Mustang/Cougar) Thinnest housing material, small axle bearings, 28 and 31 splines.
- Medium Duty: (57-68 passenger car and 1/2 ton truck) Stronger than Mustang type, 28 and 31 splines.
- Heavy Duty: (Ranchero/Torino) Thick wall housing, 3.25" diameter axle tubes with flat tops.
- Extra Heavy Duty: (69-77 Galaxies/Lincolns/Late Pickups) 3.25" diameter all the way to the backing plate. Coil housings have upper control arm mounts.
Identifying Housing Centers
- 1957: No dimples, flat center band up the center of the rear cover, bottom drain plug.
- 1958-59: Two dimples on back of housing, flat center band, some had drain holes.
- 1960-67: Two dimples, flat center band, oil level hole in back cover.
- 1963-77 (9.375" Centers): Found in Lincoln, LTD, T-Birds. Housings cut away at gasket surface for ring gear clearance; one curved rib at front top. Note: Strong, but no aftermarket gears available.
Axle Shafts & Splines
The spline count for each original axle is in the axle tag guide, by tag code.
-
28 Spline: Most are tapered and cannot be shortened.
- Exception: 69-73 Mustang and Cougars have straight 28 spline axles that can be modified.
-
31 Spline: 1972 and earlier versions can typically be shortened and resplined.
-
73-Later (Big Cars): Feature a 5-on-5 bolt circle; these axles cannot be shortened.
67-73 Mustang Identification (by wheel flange)
- Oval Hole: 28 splines.
- Two large holes & countersunk center: 31 splines.
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