Classic Design Concepts’ Weekend...
Classic Design Concepts’ Weekend Warrior SEMA project is a ’10 GT that will spend much of its post-show life on the nation’s road courses, where the strength and gear-swap convenience of Currie Enterprises’ 9-inch axle upgrade kit will be put to good use.
We’re lucky. For years, the factory has equipped the V-8 Mustang with an 8.8-inch rear axle assembly. It has earned a reputation for hardiness at power levels well beyond stockat least, in street applications, where traction usually breaks before the rearend housing.
Even so, back when the 8.8 was engineered, it’s safe to assume that nobody on the project foresaw the day of 600, 700, or 800hp street Mustangs. Nor was the housing or its internal components designed with the high-traction torture of a dragstrip or the high-heat environment of a road-course in mind. Its integrated-carrier design also complicates gear ratio swaps. All of which is to say that like every stock component, the 8.8 axle simply has its limitations.
But, as Blue Oval fans, we’ve always had an ace up our sleeve, in the form of Ford’s venerable 9-incharguably one of the sturdiest axle assemblies ever engineered. And strength isn’t the only advantage of the 9-inch design; there’s also that removable gear case, or third member, which permits relatively quick ratio or differential swaps for swift adjustment. Of course, the 9-inch axle housing itself is a rather generic beast, seeing use in everything from muscle cars to stock cars. Luckily, the aftermarket embraces the basic design, with companies like Currie Enterprises manufacturing application-specific versions.
The centerpiece of the kit...
The centerpiece of the kit is Currie’s 9-Plus Heavy Duty housing, a sturdy beast built to stock S197 width and pinion-offset specs. It is fitted with the company’s 31-spline axles, and all the necessary factory-style brackets are jig-mounted in place.
One of Currie’s latest variants is a 9-inch upgrade kit specific to the S197 chassis, meaning it is correctly sized and configured to bolt right in place of a factory 8.8-inch assembly, while allowing retention of the factory rear brakes and even ABS function. More than just a housing, Currie’s unit is an overall upgrade kit complete with 31-spline axles, a one-piece aluminum driveshaft, Currectrac lower control arms, and an adjustable third link.
That kit was just the ticket for a car like Classic Design Concepts’ Weekend Warrior projecta ’10 GT conceived for the 2009 SEMA show. Once its show duties are wrapped up, the Weekend Warrior will see street driving and open-track use at road courses around the country. Such an application will benefit greatly from both the greater strength and easier gear swaps of Currie’s 9-inch upgrade kit, which installs as a straight bolt-in replacement, as evidenced by our photos.
Also in place are ABS reluctor...
Also in place are ABS reluctor wheels, and the supplied caliper brackets are drilled and tapped for the factory ABS sensors. Your stock S197 disc brakes will bolt right on and full ABS function is preserved.
You’ll sometimes hear of designs like the Mustang’s venerable factory 8.8-inch rear, with its integral gear carrier, referred to as a Salisbury-type axle (the name of an early manufacturer). Removable-carrier axles like the 9-inch are also often called banjo-style because, in someone’s mind, that’s what their empty housings resemble.
Also in place are ABS reluctor...
Also in place are ABS reluctor wheels, and the supplied caliper brackets are drilled and tapped for the factory ABS sensors. Your stock S197 disc brakes will bolt right on and full ABS function is preserved.
The sturdy upper control arm...
The sturdy upper control arm bracket is fitted with Currie’s Johnny Joint rod end. There are a multitude of options when it comes to configuring the third member. The one for Classic Design Concepts’ Weekend Warrior has a nodular case fitted with 3.89:1 gears and a Detroit TrueTrac gear diff.
Though you can, of course,...
Though you can, of course, order the housing on its own, Currie offers a complete upgrade kit, with one-piece aluminum driveshaft, Currectrac lower control arms, adjustable upper control arm, and a supply of 85W/140 gear oil.
The factory lower control...
The factory lower control arms are stamped steel and don’t inspire much confidence as to their rigidity. Currie’s Currectrac replacements are whittled from billet 6061-T6 aluminum. They feature greaseable rod ends at the (larger) axle end, and similarly greaseable spool-type urethane bushings at the other.
Currie’s upper control arm...
Currie’s upper control arm wears a heavy-duty fork at the housing end and a greaseable rod end where it bolts to the chassis bracket. They are pre-adjusted to factory (8.48-inch) length, but can be adjusted either on or off the car to precisely establish your desired pinion angle.
Our starting point is a bone-stock...
Our starting point is a bone-stock ’10 GT rearend (aside from the FRPP springs, which, you may notice, were installed upside down.) While the length and bracket hardware has evolved over the years, the basic 8.8-inch center section is essentially unchanged from the Fox era.