Jerry Heasley
May 26, 2011

Horse Sense: Carl referred to the new speed shop at the manufacturing facility at Shelby American (www.shelbyamerican.com), located at 6755 Speedway Boulevard, right off the I-15 exit to Las Vegas International Speedway north of the city. In this specialty shop, Shelby American upgrades any make and model, not just Mustang.

Sometimes I photograph a Mustang feature and lose the owner’s contact info. In this case, we had pictures of Carl Stephens’ résumé, but we didn’t have his digits. Fortunately, luck intervened. I was shooting pictures at Shelby American in Las Vegas, Nevada, for the coming Shelby annual when Carl Stephens walked up to me and said, “Whatever happened to that shoot we did on my car?”

I recognized the face and the shoot started to come back to me. I said, “We were just trying to find you to write the feature on your car.” Carl had recently gone to work for Shelby American at the Las Vegas International Speedway. When I shot his car, he worked for a commercial concrete business. He got laid off and went to work at Nevarez Racing Products in Las Vegas. He said, “I had a job opportunity with Gil [Nevarez] to jump in as a mechanic, it was an entry-level kind of thing.”

Carl was an NRP client with his ’05 Mustang GT. Building a really fast Mustang can be an educational experience. It was for Carl, who did much of his own mechanical work and parts selection. Basically, he learned the speed shop/mechanic business from Gil and started a new career. What other new car can do this for an owner?

When Gil made the jump to Shelby-American, Carl followed. He is now head of Sales, Parts, and Scheduling at Shelby American Motorsports. He showed me his black Mustang GT sitting in the corner of Shelby American’s shop, once again undergoing more changes. “It was nice to get my feet wet over at Gil’s and then have the opportunity to work for the speed shop that Shelby was starting,” Chris said. “It’s pretty neat. I got to meet Carroll. As soon as we opened up that place, he came out and was excited to have the aftermarket side get started, and we’ve been doing well.”

Carl described his GT as a “late 2005.” He ordered the coupe new in January 2005. “I waited six months for that thing when I ordered it.” What he got was a five-speed GT in black clearcoat with a red interior upgraded to leather.

From day one he intended to modify it for street and strip—the car was never a daily driver. His goal was pretty simple: 500 hp in a “streetable” package. Carl started with a non-intercooled centrifugal that made “about 450 hp.” Shifting the stock five-speed, he recorded “consistent 12s all day long” down the quarter-mile.

Carl still hadn’t achieved his 500-horse goal and wanted more. He installed a smaller pulley and sent the car to NRP for tuning. On the dyno, the 4.6 made 525 hp. Not surprisingly, the motor blew apart running down the quarter-mile.

With a little bit of angst in his voice, Carl said, “I blew the stock motor out of it.” That’s what happens when you push the stock bottom end with boost. Carl now believes 500 hp was about the maximum the rods could handle in his 4.6. Curious, I wanted to know what happened when the engine detonated. Carl said he was in the top of Fourth gear down the quarter-mile when he felt a violent vibration coming from the floorboard and saw smoke blowing out the back end like an F-16. Later, he learned the Nos. 1 and 5 rods broke.

He towed the GT back to NRP to build a stronger motor. Gil Nevarez mentioned Oliver Ultra Light rods and Diamond pistons as two key components in the stronger build. He sent the heads to Fox Lake for porting and polishing.

Content the built 4.6 could handle more power, he bought the ProCharger that is on the car today. The F-1C blower boosted the Three-Valve to a worthy 758 hp at the rear wheels.

Carl wasn’t after maximum horsepower—he wanted the keep his black GT street-legal and driveable. Continuing that theme, he did replace the stock five-speed with a Shelby TR-6060 six-speed as his first upgrade after the engine build. The result is a street-legal but scary-fast Mustang GT with close to 800 hp to the rear wheels.

I’m just glad Carl went to work for Shelby American or we might never have caught him.

5.0 Tech Specs

’05 GT

Engine and Drivetrain

Block 4.6-liter Teksid block
Displacement 281 ci
Crankshaft ’03-’04 Cobra forged
Rods Oliver Ultra Light
Pistons Diamond
Camshafts Comp Cams
Power Adder F-1C ProCharger w/12-rib belt
Cylinder Heads Fox Lake-ported Three-Valve
Intake Manifold Stock
Throttle Body BBK twin 62mm
Fuel System Aeromotive 1000 fuel pump w/60-lb/hr injectors
Exhaust JBA long-tubes w/3-in custom H-pipe
Transmission Shelby TR-6060 w/SPEC Stage 3+ Twin Disc, Hurst short-throw shifter, and Dynatech aluminum driveshaft
Rearend 8.8-in w/Auburn 3.73 gears and FRPP girdle

Electronics

Engine Management Spanish Oak
Ignition MSD coils
Gauges Auto Meter w/Speed of Sound pillar pod

Chassis and Suspension

Front Suspension
K-member Stock
Springs Eibach Pro
Struts QA1 adjustable
Brakes Stock
Wheels Toxic 20x9-in
Tires Toyo Proxes 4 255/35-20

Rear Suspension
Springs Eibach Pro Kit
Shocks QA1 adjustable Control Arms, BMR upper, BMR lower control arms, BMR Panhard bar, and BMR anti-wheelhop brackets
Brakes Stock
Wheels Toxic 20x10-in
Tires Toyo Proxes 4 295/35-20

Photo Gallery

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