Inside the 2013 Mustang BOSS 302S build

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Grosse Ile, MI is a marshy island community situated in the middle of the Detroit River just south of the Motor City. It’s a hodgepodge of vacation homes, fishing shanties and a small airport that was once a US Navy air station where President George H.W. Bush briefly trained. The island just 25 minutes south of Dearborn even once had a weekend hideaway of Henry Ford’s henchman Harry Bennett back in the 1930′s.

Grosse Ile is also today home to Watson Engineering, a company tasked with building the 2013 Mustang BOSS 302S. This fall they have been assembling a fully engineered collection of purpose built parts, a Mustang body in white, and modified power-train components to create turn-key race cars that you can buy at your local Ford Racing retailer starting at $85,000.

The BOSS 302S is similar to the BOSS 302R, but tailored more for the hobbyist and to meet rules of a wider variety of race series including but not limited to NASA American Iron and ST2 as well as World Challenge GTS. The cars went on order last spring and are being delivered now to be campaigned starting for the 2013 race season.

The BOSS 302S is not just a hacked up race build, but an OEM level engineered turn-key race car. In the build process you can see the extensive attention to detail in bringing the car up to the performance standards desired by race drivers, but also several key modifications made for long term durability.

The BOSS 302S comes in Performance White or School Bus Yellow and only 50 will be built. Though not street legal and sold by a bill of sale, each has been serialized with their own unique VIN plate that lists its consecutive build number.

When the bodies arrive at Watson Engineering, a number of modifications take place to lighten the structure. Inner door skins and other redundant sheet metal is removed. Then metal is added in with a full race roll cage, jacking pads and a few additional structural enhancements. Front and rear tow bulkheads are added to back up the hooks you see protruding from the bumpers.

The interior gets a lightened dash structure, sans airbags, hvac and other electronics. An AIM data acquisition system with GPS is installed along with a Recaro HANS racing seat and quick-release steering wheel. In the passenger compartment is fire suppression system and a relocated battery is in the trunk. A cut off switch and safety nets complete the luxury touches. A custom center stack switch panel houses all the electrical controls.

On the track, cooling is a big deal. Up front are a heavy duty radiator as well as a set of stout transmission and oil coolers. The lightened front fascia has riveted in brake cooling collectors which duct air back to the front brakes. Handsome carbon fiber disc backing plates themselves look expensive. The rear Torsen T2R equipped rear differential also has an expansion tank and breather located in the trunk.


Underneath the BOSS 302 S gets a full makeover with fully adjustable coil over suspension with external bypass dampers. Bushings are all modified with Zerke fittings front and rear and mounting points are sealed with paint, homage to rules in some race series. The rear axle gets control arm relocation brackets for better geometry.

Anti-roll bars lose most of their rubber isolation and gain adjustable Heim joints. The front ball joints are beefed up and caster/camber plates are added for fine tuning. The electric power steering remains surprisingly, but gets a racing software patch.

The brakes are upgraded from stock with two piece 14” front rotors and 12” one piece rears. All brake lines are stainless steel and the power booster is of the prototype variety from Ford Racing. The ABS calibration is specific for racing, meaning it forgoes the Nanny State attitude of the stock Mustang, allowing for harder brake action which is home to racing.

Under the hood is a relatively stock and showroom similar 5.0 liter BOSS 302 engine. The transmission is a T-6060 6-Speed with an integrated cooling pump which routes its fluid to the cooler up front. The PCM calibration is however specific to the BOSS 302R and we presume would not be smog legal. And on that wavelength the exhaust is also relatively stock with side pipes included, and a set of Ford Racing mufflers.

What most people will see of the BOSS 302S, and likely a styling elements some BOSS 302 owners will emulate with their cars, is the giant adjustable carbon fiber wing. Also unique to the BOSS 302S is a fiberglas hood which utilizes the GT air extractors, tow hooks, Ford Racing front splitter and BOSS 302S graphics.

When all is said and done, the 2013 Mustang BOSS 302S is a bargain at $85,000. You would be hard pressed to go out and buy a BOSS 302 from a dealership and recreate this car at your own shop as comprehensively engineered for less.

And given the serialized build of these cars they are likely to be an investment as well, some day to roll across the block at Barrett-Jackson with a touted racing history. When it comes time to restore one concours correct, these photos in our gallery here compliments of Andrew Casselberry and Ford will come in handy. Enjoy.

About the author

Sam Haymart

Publisher and editor of Steed Publications news outlets including this one, ActivityVehicle.com, Motoring2.com, TheMustangNews.com and others. He has been an auto journalist since 1994 doing both freelance and self published news content online and in print.