While the Fox Body Mustang and its Capri cousin were pretty darn good when they came out in 1979, a lot has happened since then (including, like, 40 “Star Wars” movies).
…But we digress. One of the most notable breakthroughs in updating the Fox platform is the “Short Long Arm” front suspension design—an idea that helped earn Detroit Speed a New Product Award in the Street Performance category at the 2025 SEMA Show.
Available as a complete package, the Detroit Speed Short Long Arm (SLA) Suspension Conversion Kits update the Fox Body front suspension* to a modern double wishbone design. This system replaces the outdated factory suspension with modern geometry, which will dramatically improve your Fox’s handling performance.
Or, as the Detroit Speed folks say:
Detroit Speed’s exclusive frame rail insert optimizes camber gain and roll center height, significantly improving front-end stability. The tubular upper and lower control arms reduce deflection, providing precise suspension movement and sharper handling response.
These Detroit Speed kits are stronger than the OE setup and, depending on the kit you choose, offer a significant amount of adjustability, so you’re able to fine-tune the cornering capability of your Mustang or Capri.
The Detroit Speed gang even displayed one of these kits installed in a modified mockup Fox chassis to showcase at their 2025 SEMA booth. Suffice it to say, the fit and finish was excellent.
As an added bonus, the kits use all new five-lug hubs with forged aluminum uprights and modern bearings. Better still, the Detroit Speed team says the system was designed to work with S550 Mustang (2015-24) brake system, which means you’re able to make a big upgrade to your stopping performance with these kits as well.
For wheel/tire options with this new SLA retrofit, Detroit Speed tells us you’ll have enough clearance for 275/35R18 tires on a 10 inch rim, while still maintaining full steering lock.
The kits are designed and made in Detroit Speed’s new digs in Mooresville, North Carolina, and you’ve got a trio of options to choose from. Click the part numbers below to see pricing and availability.
- DSR-032096DS – Detroit Speed Fox Body SLA Conversion, Non-Adjustable Coil-Overs
- DSR-032096-SDS – Detroit Speed Fox Body SLA Conversion, Single-Adjustable Coil-Overs
- DSR-032096-DDS – Detroit Speed Fox Body SLA Conversion, Single-Adjustable Coil-Overs
* An Important Note on K-Member Fitment for the Fox Chassis
If you’re a Fox Mustang/Capri aficionado, then you probably know that Ford made three versions of the Fox Body K-member over the course of its 1979-93 production run. Detroit Speed highly(!!) recommends that you measure the Center to Center distance of the lower control arm mounting holes to determine which K-member you’ve got.
The Detroit Speed SLA Geometry is optimized for use with later 1988-93 K-members. So if you’ve got a 1987 or older version, you’ll need to source a replacement from an 1988-93. (It’s also worth mentioning that some 1988-93 four-banger Foxes often used a pre-1988 style K member as well.)
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