In drag racing circles, the Fox body Mustang has been perhaps the single most popular choice for racers — from the novice through veteran ranks. Aside from building a complete new car, the popular modification has been to mini-tub the back end to get wider tires underneath.
However, with the stock control arm setup on the Fox body, tire width has been limited. Moser Engineering takes that limitation to their M9 differential housing and as Tim Irwin explains, “Most of the Fox bodies have the lower control arm mounts way out close to the wheel, so I moved them in so they’re parallel with the front mounts.”
This modification on the M9 housing allows for narrowing the housing up to six inches per side versus the two inches on the standard mounts. It allows for mounting up to a 13-inch tire with mini-tubbing, and the bonus is that there’s minimal welding.
An upper crossmember welds in above the housing with upper coilover shock mounts and a built-in adjustable anti-roll. There are infinitely adjustable upper and lower mounts on the housing, and double adjustable upper and lower control arms to make the tuning much easier, as well as adjustable coilover shock height.
Irwin said, “What a lot of the Mustang guys run into with the 8.8 and 9-inch bolt-ins is that it raises the upper mount way up, and running a power-adder it makes the car separate too much. With this, they can change that instant center and get it out further forward in the car and make it a lot more tunable.”
For narrowed widths, if a customer can provide the dimensions they can build the housing to spec. Irwin says they’ve had enough customer feedback that they felt it was worth doing. Plans include upgrades for the GM A and G body cars to incorporate wire tires in 2015.
To learn more about the M9 and all of the other components for street and race cars, be sure to visit the Moser Engineering website, and expect to see this Fox body housing hit the market this week.