Jim Smart
May 19, 2010

It's been five years since the S197 Mustangs first hit the highways for the '05 model year. Carl Stephens was among the first to buy one. When he took delivery of his '05 GT coupe, he began his journey with cool modifications befitting Ford's newest and hottest Mustang since 1964. He started with a Classic Design Concepts' chin spoiler and side scoops, along with huge 18-inch Saleen wheels. The car looked terrific, but didn't have the power to back up the persona. So Carl bolted on a Vortech SQ-Trim supercharger, which pushed horsepower to 480 at the tires after a tune from NRP Racing in Las Vegas.

Carl made over 100 passes at Las Vegas Motor Speedway, getting his Mustang into the low 12s before pushing his 4.6L-3V SOHC to T-Trim level with 520 rear-wheel horsepower. That upgrade came with a price when Carl blew the engine in search of lower elapsed times. Failure came from oil starvation due to pieces of piston skirt wedged in the pick-up, causing a pair of rod journals to fail and sending them through the oil pan.

Carl didn't allow the engine failure to slow him down. Using the set-back as a springboard to even greater power, he went to Gil Nevarez at NRP Racing to plan out a stouter 4.6L powerhouse with 5.933-inch Oliver rods, forged Probe pistons, and a steel six-bolt crankshaft. For more power, Gil added a 62mm Granatelli Motor Sports throttle body, greater fuel rail capacity, and larger injectors. The three-valve heads went to Fox Lake for Stage III CNC-porting and polishing with stainless steel Manley valves and an aggressive cam duo from Comp Cams. On top went a Procharger F1-C supercharger with a 12-rib blower drive and race intercooler. The result was 602 hp and 520 ft. lbs. of torque. Achieving these numbers required 10 pounds of boost on 91-octane pump gas.

Carl's goal is to bolt on a 20-pound pulley, huff up fuel delivery with a second pump, and get his S197 rocket ship into the high 700, low 800hp range to crack a 10-second quarter-mile in street trim. He plans to get there with help from MAC ceramic-coated long-tube headers through 2.5-inch primary tubes along with huge 3-inch collectors and pipes.

When you throw this much power at a Mustang chassis, you're courting disaster if you don't adequately prepare with the right parts and precision suspension tuning. Carl opted for an Eibach Pro Kit with adjustable QA-1 shocks and 20-inch Toxic rims wrapped in Toyo Proxe 4s with a 45mm offset. Tire size is 255/35/20 front and 295/30/20 rear. BMR control arms along with an adjustable panhard bar improve stability. Carl also stepped up to slotted and cross-drilled brake rotors.

For a nice street/strip demeanor, Carl went with an Auburn Gear 3.73:1 8.8-inch differential with 31-spline axles. With this axle ratio and Tremec five-speed, revs remain conservative at 75 mph. And when it's time to go drag racing, gear one through four get the job done. A Hurst short-throw shifter makes it easier to get there. Denny's Driveline provided the one-piece driveshaft.

Carl considers himself fortunate. He has a successful business, terrific wife, three kids, and a good life in Las Vegas. "This is my first new car in 16 years of marriage and I look at it as a compromise because I bought my wife an '06 Mustang V-6 convertible for some flexibility-or perhaps to buy her off," he says with a smile.

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