Mark Houlahan
Tech Editor, Mustang Monthly
June 1, 2013

The late-model Ford corporate 8.8-inch axle housing has been around since the early 1980s. First used in the F-150 truck, the 8.8 (pronounced "eight-eight" in bench racing vernacular) found its way into many corporate installations including the '86 to current Mustang. Ford replaced the aging (and heavier) 9-inch with the 8.8 to retain a strong rear axle for its truck lineup (it was also used in Explorers, Rangers, and fullsize Broncos), while reducing overall weight as well as rotational mass for increased fuel economy. While the 8.8 has some inherent weaknesses (axle bearings for one), it is considered a robust axle with huge aftermarket support. It is not uncommon today to see the 8.8 axle taking the punishment of 800-plus-horsepower race cars or digging into the dirt in off-road circles.

The commonality of the 8.8s internals combined with the huge installed base means finding one used is as easy as stopping in to your nearest recycling yard. Of course, if you're looking for something "built," many aftermarket axle companies like Moser, Strange, Drivetrain Specialists (DTS), and others can build you the exact assembly for your needs. Due to the 8.8's popularity, it was only a matter of time before someone tried to stick one under a classic Mustang. Early adopters utilized the Ford-Explorer-based 8.8, as the Explorer is a leaf-spring-equipped vehicle. Most installers simply torched off the spring plates and installed new ones in the right location and the axle was a bolt-in (sort of) with the bonus of rear disc brakes, Traction-Lok differential, and usually a nice 3.73 gearset. However, the Explorer axle uses an offset center. This often created driveline angle issues, including vibration and even contact with the sheetmetal tunnel/floor in extreme suspension compression. The answer was to use an 8.8 axle that had a centered housing, but the only option for a centered housing is the '86 and later Mustang 8.8, which is mounted via a non-parallel four-link and coil springs.

While the Mustang 8.8 can certainly be modified in a similar way to the Explorer housing by welding on new brackets, and so on, the idea of simply making the housing a true bolt-in became the brain child of Anthony Jones of AJE Racing. Anthony's success with bolt-in front suspension cradles for late-model Mustangs had blossomed into similar coilover strut kits for classic Mustangs and Fords, so he was already familiar with using late-model Mustang parts to improve the classic Mustang (AJE Racing's front suspension kits utilize late-model Mustang struts, spindles, and brakes). He envisioned a suspension cradle that turned the '65-'70 leaf spring Mustang into a true four-link with coilover shocks that allowed the use of the modern 8.8 axle housing. His new cradle allows just such an installation and AJE offers both fixed and adjustable control arms, an antisway bar option, and more. Check out the new AJE setup here that Chris Rose of Innovators West is installing in the company's '65 Mustang project.

1965-1970 Mustang 8.8 Axle Housing Conversion Parts Used

While AJE does offer two different rear suspension packages, it does offer all pieces individually. Chris chose the following parts for his 8.8 installation:

MR-1000 Rear Suspension Cradle $349
MR-1100 Bushed Lower Arms $199
MR-3310 Adjustable Upper Arms $229
MR-3800 Antisway Bar $349
MR-3900 Spherical Upper Bearings $99

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25. Back on the ground using some mock-up shop wheels, Chris’ ’65 coupe is ready for finish bodywork and paint while the Kaase big-block gets screwed together. We’re sure we’ve not heard the last about this project.