KJ Jones Senior Technical Editor
January 4, 2007
Photos By: KJ Jones

Horse Sense: With all due respect to the new age of 'Stangbanging, part of our mission with our project '86 T-top coupe has been to keep Fox Mustangs in people's minds, and do our part to try to ensure there will never be any true, all-out end to one of the most popular platforms in Mustang history.

When all is said and done and our T-top-coupe project is complete, no one will be able to dispute the fact that the car and the project helped bring about some cool, new technology for '79-'93 Fox 'Stangs. This is significant because it has been more than 25 years since the popular Ponies were introduced.

We're technically now in an era that can be considered the twilight period/swan song for the Fox platform. Enthusiasts' interest in 'Stangs of this vintage is beginning to fade, thanks to the steady rise of S197 performance and the unofficial recognition of Two-Valve, '99-'04 cars as today's Mustang of choice.

Let's face it. The '86 T-top coupe we've been working on since February 2006 is a 20-year-old classic, albeit rare, Mustang. It has been great having companies embrace our idea of never forgetting the 'Stangs that started the movement, and investing their time and resources to create new products for Foxes at this stage in the game.

One of the new Fox concepts we've been stoked about is this FAB9 rearend and rear suspension from Chris Alston's Chassisworks, the noted chassis-component company that also developed the T-top-specific Mustang rollcage we featured in our July '06 issue ("'Cage Match," p. 176).

We first met Chris Alston Sr. at the '05 PRI show in Orlando, Florida, and spoke with him about our project. Chris explained that Chassisworks did not offer anything made specifically for Mustangs, but said he was interested in doing so and wanted to hear more.

After listening to our vision of bringing the rare 'Stang back to life in the form of a real-world, street/strip ride featuring new concepts in areas we considered necessary at this juncture or that would be accepted as cool by many of our readers, Chris wholeheartedly embraced the project. A short month after hauling the coupe to Chassisworks' massive headquarters in Sacramento, California, we were looking at the all-new, Fox-specific version of the company's fabled FAB9 rear, as well as upper/lower control arms, a coilover rear-shock system, and an adjustable antiroll bar, that we've been anxious to tell you about.

Now, before those 'Stang enthusiasts/ purists who have bashed this project from the outset mount a knee-jerk-reactionary letter or Internet-post campaign to complain about these suspension pieces being "one-off," or "custom," or even "unnecessary," we suggest they read this entire report.

As we've said in prior reports, one of the cooler aspects about the reconstruction of this ride is that we've been able to use parts-we like to use the term shelf parts- that are available for anyone to purchase at any time. We're trying to stay away from the over-the-top custom stuff that oftentimes goes far beyond the realm of doable for many readers' budgets.

With that said, yes, the parts developed by Chris Alston's Chassisworks are expensive; there's no disputing that. We also know that a stout 8.8 can be assembled for less money, and if done right, can have the same 1,000-plus-horsepower capability as our rear. But if you're really interested in bolting on the ultimate in hassle-free, direct-fit, bulletproof, 9-inch rears under your 'Stang, you'll definitely want to con-sider stepping up to a FAB9 housing and completing it with Strange axles, third member and gears, a Detroit Locker for street/strip or spool, and Wilwood rear brakes, as we did.

As mentioned earlier, our coupe's mild-steel FAB9 (chrome-moly is available as an option for the rear housing and upper/ lower control arms) is complemented by the new rear-suspension system that Chassisworks developed. The suspension parts are centered on adjustable Pro-Upper and Pro-Lower control arms and equally adjustable VariShock rear coilovers. The cool thing about the shock mounts is that they are positioned in the factory location and maintain their OEM shock angle, which many classes in the popular Mustang drag-racing sanctions require. One thing to note about both the upper/lower arms and the shocks is that Chassisworks has incorporated provisions for up and down adjustment into their mounting points on the FAB9, which expands the range for lowering a Mustang, or making adjustments that optimize launch characteristics (hooking and going straight) when you're at the dragstrip. A unique antiroll bar rounds out the Chassisworks suspension system. We also added Maximum Motorsports' full-length subframe connectors to tie the front to the back, as those parts are not available from Chassisworks.

After assembling the FAB9 in the driveway, we carried the rear and other suspension parts down to B&D Racing in Canoga Park, California, for installation. The parts can be bolted on at home in do-it-yourself fashion, but be aware the rearend is burdensome and might be a struggle to muscle into place. At B&D, everything went smoothly for Mason "Mase" Rowland, the shop's lead technician who handled the install for us. Once Mase got our coupe set up a twin-post lift, the entire installation came together in about five hours.

The photos say more about how trick this setup really is. We're using the street/strip setup with poly bushings, but a full-on race deal is also available.

Mason "Mase" Rowland of B&D Racing starts the goodbye process for the project car's stock 8.8. We're yanking this unit of unknown gearing and condition, and replacing it with the all-new, bolt-in FAB9 rear by Chris Alston's Chassisworks. Note the bracket mounted on the frame, to the right of Mase's hand. That's for one of the antiroll bar links. Both link brackets were permanently installed by the crew at Chassisworks, who used our car for the development of this new Mustang rearend and suspension system.

Here's a look at the complete FAB9 rearend housing, Strange Engineering's 35-spline Street/Strip (S/T) axles, nodular-iron S-Series case (loaded with 4.11 gears and a Detroit Locker differential), and all the rear-suspension components. The mild-steel FAB9 (PN 84M40-30 w/back brace and antiroll bar; $1,227) is shipped in raw metal form, so Johns Customz and Performance took care of colorizing ours while the car was being painted. Since the development of our FAB9 rearend in February 2006, Chris Alston's Chassisworks has added six additional bolt-in FAB9s for Fox through S197 Mustangs, available in mild steel or chrome-moly, and including poly or spherical bushings. Housings can be shortened between 11/44 and 3 inches (for mini-tub applications) at no additional charge. We suggest you call Chassisworks to speak with someone there who can help you select the rear that best suits your needs.

Assembling a FAB9 rear is an easy driveway job. Our buddy, Nitrous Dave Rooke, had supposedly stopped by "just to have a look" at the FAB9, but he couldn't suppress the urge to be involved. Here, Dave preps the housing for assembly. It's important to thoroughly clean the housing and chase all the threads for the case studs. Check out the Strange S/T axles in the background. These 35-spline axles are 1.5 inches in diameter and more than strong enough to handle the 600-or-so horsepower we hope to put down.

This is the Strange Engineering S-Series case for our FAB9 (PN PRF-130; $1,279 complete). This nodular-iron unit features a 35-spline Detroit Locker automatic, positive-locking differential, and 4.11 Strange gears. A 1350 yoke is standard with this setup. Some of you are thinking that a 4.11 gearset is too steep for highway cruising with our blown, 347 stroker engine combo, but we're fairly confident the Overdrive gear in our Performance Automatic AODE transmission should kick the revs down sufficiently. The locker differential utilizes a spider assembly and driven clutches that lock together when driving in a straight line, and ensures maximum traction at both rear wheels at all times. But, in true posi-traction form, the Detroit Locker can allow wheel speeds to differ when required-such as when turning or driving over uneven surfaces.

After cleaning the FAB9 and installing the mounting studs for the case, Dave seats the Fel-Pro 9-inch housing gasket (PN H1111; $13.20) and uses our Snap-on electronic torque wrench (PN TECH2FR100; $323.50) for spot-on accuracy as he secures the locking nuts with 30 lb-ft of torque.

Strange's S/T axles and bearings (PN 3502; $369.60) are installed once the diff has been secured. We have 35-spline axles that measure 2731/48 inches for the driver side and 3011/42 inches on the passenger side. Wilwood's Dynalite Pro Series rear-disc brake kit (PN 140-6696-D; $783.28) features SRP slotted and drilled, 0.50-inch-thick, 12.19-inch-diameter cast-iron discs, four-piston calipers, and PolyMatrix 7112 "T" compound brake pads. We decided to use this brake setup as opposed to Wilwood's lighter, steel race brakes, mainly because this car will see a generous amount of street use. The cast-iron rotors are better for the street because the iron handles the constant heat developed by street driving better than steel. Steel is the way to go for drag racing, as excessive heat is only built up in short bursts at the end of each run, and then the brakes are allowed to cool down.

Tying the front and rear subframes of any-year Mustang is a must-do task, especially if you have-or plan on putting some-respectable power under your 'Stang's hood. We're hooking our project car's front to its back with Maximum Motorsports' full-length subframe connectors for '79-'93 Foxes (PN MMFL-1B; $119).

After welding the connectors, we gave them a shot of black paint to protect them from corrosion.

The bottom of a Mustang doesn't get much exposure unless the car does monster wheelstands on the dragstrip, but we decided to spruce up the undercarriage prior to installing the FAB9 and rear suspension. Nothing fancy, just some black spray paint.

Prior to installing the VariShock Quick Set I double-adjustable rear shocks (PN VAS11211-515; $648/pair), the coil-spring seats for both 12-inch, 150-pound coilover springs are treated with a slight coating of antiseize.

Mase initially adjusts the Chassisworks Pro-Lower Control Arms (PN 5807-M40; $439/pair) to the same length as the stock control arms. The tubular Pro Lower arms feature 12mm mounting bolts and high-quality rod ends that make dialing-in critical suspension adjustments easy.

Here's a close-up look at the upper shock crossmember for our new VariShock coilovers. The upper mounts bolt into the factory shock housing. Drilling a few simple holes is required here, but the bracketry is sanitary, and when installed, maintains the shocks' original angle.

Mase bolts in the Pro-Upper Control Arms (PN 5808-M40; $239/pair) on our project T-top coupe. As with the lowers, these stout, double-adjustable upper arms bolt directly in place and allow for major pinion-angle adjustment.

With all the arms in place, our FAB9 rear and Chris Alston's Chassisworks suspension are ready for final installation. Mase connects the upper arms to the housing and pumps the housing into position with a transmission jack. This is the best way to install a FAB9. It's a hefty piece, which is great for 'Stangs that count on weight in the rear for traction, such as Drag Radial cars, but hiking it into place without a jack is not worth the risk of getting hurt

Here's a close-up look at the parts that make up the Chassisworks 'Stang rear suspension: Pro-Upper and Pro-Lower control arms and a VariShock rear coilover. Check out the large-diameter end for the axle bearing and the billet lower shock mount. Chassisworks incorporated three-position (up/down) adjustment for the shocks and a two-point variance in where the lower control arms can be positioned on the FAB9 housing.

The engineers at Chris Alston's Chassisworks designed the Mustang FAB9's antiroll bar setup with a full exhaust in mind. The antiroll bar (PN 5806-M40; $379) actually mounts below the rear, instead of up and over the axles and across the bottom of the trunk floor, providing plenty of clearance for running exhaust systems all the way back. The bar is comprised of a 111/44-inch steel rod with 48 splines machined into each end. Billet-aluminum arms and end adjusters complete the setup. The antiroll bar has become one of the more critical components in a Mustang's suspension, as it allows a racer to adjust chassis preload to achieve the best traction possible.

The Frontal Approach
Of course, the front suspension of our car is equally as important as the rear. We decided to go with Racecraft's '79-'93 Mustang K-member (PN 32735000000E), A-arms (PN 3212BU00), caster/camber plates (PN 340001), bumpsteer kit (PN 3332000), and 2-inch drop spindles (PN 300102) to anchor the front points of our 'Stang. We provided the details on this setup in our Dec. '05 issue ("Off the Bumper," p.108), so check it out.

After debating long and hard about keeping the car's power steering intact-Editor Turner voted for power steering-we decided to do away with that convenience and added a quick-ratio manual rack-and-pinion setup from Flaming River (PN FR1520), as well as the company's make-it-to-fit steering-shaft assembly.

Wilwood's Dynalite Pro Series front-hub brake kit (PN 140-7589-D; $844.40) was chosen as the slow-down apparatus for our hopefully speedy coupe. The system features forged billet hubs, four-piston calipers, and vented front rotors measuring 10.75 inches in diameter. Wilwood's PolyMatrix brake pads complete the brake system.

Completing this leg of our project allowed us to finally rid the car of the four-lug Pony wheels it has been rolling on since shortly after we got it in October 2005. For now, a set of replica Shelby GT 500 17x9-inch bling from American Muscle (formerly Mustang Tuning) and Nitto's NT555 Extreme ZR rubber has been mounted up front, and NT Triple-Five-R Extreme Drag Radials adorn the two wheels at the rear of the T-top coupe.