9” Ford Facts
Common axle widths
65-66 Mustang 57.25 inches
67-70 Mustang 59.25 inches
71-73 Mustang 61.25 inches
77-81 Versailles 58.50 inches
74 Maverick 8" 56.50 inches
75 Mustang II 8" 57.00 inches
67-73 Mustang, Torino, Ranchero, Fairlane 9" 59.25 inches to 61.25 inches
57-59 Ranchero and Wagon 57.25 inches (narrowest 9" housing)
66-77 Bronco 9", 58 inches (has 5-on-5 1/2 inch diameter bolt circle)
77-81 Granada/Versailles, 58 inches
67-71 Comet, Cougar, Mustang, Fairlane, 59.25 inches
64 Falcon 58 inches 67 Cougar 60 inches
67 Fairlane 63.50 inches (coil springs)
72 Ford Van 3/4 ton 68 inches
67-73 Torino, Ranchero, Fairlane 59.25 inches or 61.25 inches
67-71 Comets, Cougars, Fairlanes 59.25 inches
Where to find the 9" rear axle
67-73 medium and big block Mustangs and Cougars-66-71 Fairlanes, Torinos, Montegos, Comets, and other Ford intermediates with big blocks-57-59 V8 Fords and Mercurys-77-81 Lincoln Versailles & Trucks Types of 9" axle housings 67-73 Mustang/Cougar - light duty, thinnest housing material, small axle bearings, 28 and 31 splines 57-68 passenger car and 1/2 ton truck - medium duty, stronger than Mustang type, 28 and 31 splines
Ranchero/Torino - heavy duty thick wall housing, 3.25 inch diameter axletubes with flat tops 69-77 Galaxies (coils), Lincolns (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 recognize 9" housing centers
57 - no dimples, flat center band up the center of the rear cover, bottom drain plug
58-59 - two dimples on back of housing, flat center band, some had drain holes
60-67 - two dimples, flat center band, oil level hole in back cover
63-77 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 gear options.
9" Axle Facts
28 spline axles cannot be shortened, except 69-73 Mustang and Cougars, because they're tapered.
72 and earlier 31 spline axles have the ability to be shortened 73 and later 9" (big cars) have a 5-on-5 bolt circle and the axles cannot be shortened