The Boss Hoss Mustang is yet another YearOne project car that’s served multiple purposes. Built in 2004 to coincide with the release of YearOne’s classic Mustang catalog (covering 1964-1/2 to 1973 models), the car also helped establish our tradition of debuting new project cars on the Hot Rod Magazine Power Tour.

Another tradition the Boss Hoss has upheld is the YearOne build style of combining classic muscle car looks with late-model running gear. We build cars like this simply because we think it’s hard to improve on the iconic styling of the early cars, and it’s also hard to argue with the performance, reliability and driveability of late-model powertrains.

As such, the Boss Hoss is powered by a 2003 Mustang Cobra supercharged 4.6 liter V8. In stock form, these engines make a reliable 390 horsepower. We’ve tweaked it a bit for more, of course, but more on that later.

Backing up the blown mod motor is a Tremec 6-speed, also out of an ’03 Cobra. In the back is a 4.11 geared 9-inch rear axle assembly from Moser Engineering. Early plans called for using the Cobra independent rear in the Boss Hoss, but we determined the only real way to get the IRS in place properly would require flaring the rear fenders or completely redesigning the rear control arms. Neither was an attractive option to us, so we went the Moser 9-inch/4-link route instead.

Back to the engine – the first thing we did was swap the OEM blower for a Kenne-Bell screw-type unit. The KB blowers are more efficient than the Eaton/Ford unit, and when talking superchargers boost and efficiency are keys to big power. We also went with a Metco Motorsports Solutions pulley arrangement, both for looks and, in the case of the crank pulley, more boost. We can create more boost by altering the size of the crank pulley – larger for more pressure, and smaller for less. After some experimenting, we settled on a 14-lb pulley for street use with pump gas. With race gas we can swap on a bigger crank pulley that will make about 21 pounds of boost – and cranks rear-wheel horsepower into the 570 range. Not bad for 280 cubic inches!

Installing the DOHC engine in the early Mustang engine compartment meant doing away with the OEM shock towers. Using a Martz front subframe assembly allowed us to cut away the shock towers for engine clearance, and also provided us with modern suspension geometry and improved strength and stiffness. Tubular control arms with heim joints are a feature of the Martz setup, and QA1 adjustable coil-over shocks provide the adjustable ride height. Wheels are from Billet Specialties, Stainless Steel Brakes Corp. supplied the binders, and BFGoodrich rubber provides the traction.

Outside the car, the first thing most people notice is the carbon fiber hood that’s patterned after the famous Thunderbolt design. We wanted a carbon fiber piece in a vintage style to reflect the overall theme of the car – classic looks with modern performance. Other body mods are minor, and include the use of a ’65 grille with upgraded flat halogen driving lights hidden behind it, and a subtle rear spoiler. It’s hard to improve on the classic fastback Mustang look, so not much is necessary here. For paint, we chose an ’03 Mach 1 color, Azure Blue, with black accents to complement the carbon hood.

Inside the car we took a set of late-model Mustang seats, zapped the headrests and made a set of custom black and blue seat covers. We updated the instrument panel with AutoMeter Cobalt blue gauges in a custom housing, and of course, added a thumping sound system for those long hours on the road. For safety’s sake, we added a 6-point roll bar and a set of race harnesses to keep the occupants in place.

The Boss Hoss has been on multiple Power Tours now, and has had a number of drag strip blasts and quite a few laps around the Road Atlanta road course. Reliability has been good so far, particularly considering the power levels the car is capable of reaching. About the only thing we’re constantly changing is rear tires, but that’s to be expected with a bad, blown Mustang.

Engine & Driveline:

• Modified 2003 Mustang Cobra engine
• Kenne Bell supercharger
• Metco pulleys
• Accufab throttle body
• FAST engine management system
• T56 6-speed transmission
• Kirban shifter mechanism
• RAM clutch
• DynoTech Metal Matrix driveshaft
• Moser 9-inch Ford rear axle with 3.73 gear and Detriot Locker differential


• 18” x 10” rear, 17” x 7” front Budnik Formosa wheels
• 295/35/18 BFGoodrich G-force drag radial rear, 215/45/17 G-force T/A radial front.
• 13-inch Stainless Steel Brake competition disc brake system
• Lokar e-brake cables


• Martz Chassis tubular front subframe with tubular control arms and Mustang II type spindles
• Martz Chassis rear four link with competition rear sway bar
• QA1 adjustable coil-over springs in front and rear


• 1966 Fastback
• Rear area of body and frame is mini-tubbed for tire clearance
• Custom boxed frame connectors
• Carbon Fiber A/FX inspired hood
• The lower valance is modified with custom intercooler duct
• Fiberglass spoiler integrated rear deck and 1/4 endcaps
• Hella driving lights are incorporated behind grille


• 2004 Mach I Azure blue and black
• Primers and clears by Southern Polyurethane
• Body and Paint by WillFab Rod Shop (Jerry and Brian Williams)


• 87 Mustang GT bucket seats
• Seat upholstery and carpet by Lamar Stevens
• Vintage Air conditioning system
• Auto Meter Cobalt prototype in-dash gauges
• Rockford Fosgate AM/FM/CD player with 5” integrated speakers and 10” subs
• Monster Cable used throughout

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