KJ Jones Senior Technical Editor
January 4, 2007
Photos By: KJ Jones

Horse Sense: Horsepower is our business. Well, it's actually just one facet of our business, but it's probably the aspect we dig the most, especially when we're talking about how to make more and the 'Stang or engine we're working is "bone stock." For this exercise, we're definitely not talking about any bone-stock Mustang.

With Ford's '07 Shelby GT 500 now officially out, and dealers are raking in major coin for them ("average" above-sticker prices are said to be in the $70,000 range; some Shelbys reportedly purchased for as much as $90,000), we've been watching the roads in Southern California to see whether enthusiasts who purchase the 500hp mega-Mustangs are actually driving them, or if they're immediately stowing the cars, hoping that a grand payday at the Barrett-Jackson Auction is in their future.

We're happy to report that while Shelbys may not be as dime-a-dozen as Foxes or New Edge 'Stangs, several of these special-edition, blown, 5.4 models have been spotted in the Los Angeles area. It also appears that owners have been quick to personalize and modify them.

Galpin Auto Sports, aka GAS (a division of Galpin Motors) of Van Nuys, California, is the newest player in dealership-operated, high-performance upgrade centers for Mustangs and other Fords. When we decided we wanted to be one of the first magazines to take a stab at upgrading a GT 500 for more horsepower, we contacted Steve Carpenter at GAS because we knew he could produce a Shelby for us in a short timeframe. In less than two hours, Steve had us on the phone with Tom Pence, the owner of the black and silver-striped GT 500 you see in this report.

Tom is the kind of enthusiast we love. After detailing our intentions and assuring him our upgrades would in no way prevent him from returning the car to stock trim at any time-we're betting he won't-Tom gave the OK for Galpin's technicians to install a Lightning Force Performance Stage 1 Power Package (PN Shelby Power Pack; $469) on his brand-new ride.

LFP's entry-level upgrade for Shelby 'Stangs includes one of two interchangeable Quick-Change billet-aluminum upper pulleys (2.80- or 2.60-inch) for the blower, a high-grade-steel mounting hub, and Allen-head fasteners. A machined idler pulley of 100 mm is also included (for the 2.60-incher only) and provides increased tension on the Shelby's wide belt to ensure it stays secure when the supercharger is at full whine. Aftermarket belts for the GT 500's supercharger were not available at the time of our test, but LFP says it should have 10-rib, poly-cog-style belts in stock by the time you read this.

Increased boost (as much as 4 psi with the 2.80-inch pulley and 6 psi with the 2.60-incher) creates increased cylinder pressure and heat and changes the engine's air/fuel ratio dramatically. To compensate for this, each Stage 1 Power Package includes SCT's XCalibrator 2 handheld flash programmer, loaded with a custom tune created by Andre Terranova of Custom Performance Tuning in Houston, Texas.

Spark is also a big concern whenever boost increases, so we're installing a set of high-output coil packs and coil-on-plug connectors by Lightning Force Performance. The coils increase spark plug voltage, which keeps the flame of combustion lit under higher boost conditions.

Of course, none of this is being done simply for the sake of doing it. Our primary mission is to obtain data-in this case, horsepower, torque, and boost-and the best way to do it is by giving Tom's Shelby GT 500 a good workout on the Dynapack Evolution 4000 chassis dyno at Extreme Automotive, once the pulleys and tune have been installed.

What were the results? Well, the Shelby GT 500 is already no slouch in bone-stock trim (the "500" in its name represents 500 flywheel horsepower). We know you're asking, "How much better-or worse-does this Four-Valve 5.4 become when influenced by a simple bolt-on and some computer technology?" Read on.

Here's a look at the brand-new (only 15 miles), bone-stock bullet in Tom Pence's new Shelby GT 500. While we're only swapping out the stock 3.00-inch upper pulley, ignition coils, and revised Silver Oak programming, we think the upgrades should add quite a few additional horses.

Lightning Force Performance offers this easy-to-install Stage 1 Power Package for '07 Shelby GT 500s. We're using the 2.80-inch replacement upper pulley and steel hub shown in the photo, but a smaller, 2.60-inch piece is available. SCT's XCalibrator 2 programmer and LiveLink/LiveUpdate software are also included as part of the package. A billet-aluminum, CNC, 100mm idler wheel is provided with the 2.60-inch upper pulley. This larger idler wheel reduces belt slippage when the smaller upper pulley is used.

Also shown, but sold separately, is LFP's Pulley Puller ($89). This makes quick work of removing the stock piece and installing the hub.

The crew at Galpin Auto Sports is handling all the mods being made on this new 'Stang. Lead technician Axel Chinchilla begins this segment of the project by removing the stock Autolite Platinum spark plugs and regapping them to 0.028 inch.

Closing the gap on the factory plugs works for this upgrade, as the 2.80-inch pulley increased boost more than 2 psi. We're using LFP's high-output coils, which should keep the spark hot throughout the combustion cycles.

LFP coil-on-plug connectors ($399) feature stainless-steel connector cables and snap-lock spark plug connectors. We're using the LFP coil packs and connectors because they increase voltage to the spark plugs by about 25 percent, which is more than sufficient for the GT 500's enhanced power-adder.

Axel uses a small pick tool to extract each coil connector plug from the wire harness and turns each plug 360 degrees. He reconnects the plugs to the harness to achieve reverse polarity. This is a critical step when installing high-output coils on a Four-Valve engine. Failure to reverse all eight connectors will damage the coils, and possibly damage other electrical components in the car.