Don Roy
July 1, 2008

Shelby GT Procharger
The '07 Shelby GT special-edition Mustang was made available in response to an enormous demand for a retail version of the Shelby GT-H Mustang, which could only be had as a rental car from Hertz. Aside from the obvious visual cues, these cars were substantially modified in Shelby's Las Vegas facility before delivery to the customer.

A {{{Ford}}} Racing Handling Pack with specially tuned dampers, unique sway bars, and a front strut-tower brace began the chassis transformation. New coil springs dropped the overall ride height by 11/2 inches for a more aggressive stance and reduced body roll. High-performance P235/50ZR18 BFGoodrich g-Force T/A KDWS tires maximize the benefits of the chassis upgrades. Coupled with a 3.55 rear-axle assembly for extra off-the-line acceleration, the Shelby GT is an everyday driver that's tuned for command performances at the track.

As it came from the factory, the '07 Shelby GT was rated at 319 hp and 330 lb-ft of torque at the flywheel. The car's V-8 engine is modified with Ford Racing's Power Upgrade Package, which includes a 90mm cold-air intake and a new performance engine calibration system for improved response. The high-flow exhaust system with x-style-specific crossover offers better power delivery and a throaty exhaust note that makes this car unmistakably a Shelby.

The Shelby GT is a more dynamic, more engaging version of the Mustang GT, with sharp reflexes and a track-ready suspension, but for this car's owner, it still wasn't enough. That was when he got into discussions with Terry Johnson at Street Lethal Performance, in New Castle, Pennsylvania. Johnson runs a Mustang performance shop that caters to all power-adder approaches, and he's also known as a specialist in 5.4L engine conversions for the Mustang.

In this case, the best decision was to rely on the tried-and-true supercharging route. An ATI ProCharger HO Intercooled System (PN 1FP214-SCI) with a P-1SC-1 head unit and three-core intercooler was Johnson's product of choice.

When the owner dropped off this pearly white gem, the first order of business was to strap the car onto the shop's Dynojet Research dyno to establish some "before" numbers. That run showed the Shelby was putting out around 274 rwhp and 297 rwtq. Then, it was time to get to work. Let's join the guys at Street Lethal and see what's happening.

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