CUSTOMIZED SUPPORT VEHICLES GIVE GM PERFORMANCE DIVISION A BOOST FOR BONNEVILLE SPEED RUNS

WENDOVER, Utah - In basketball it's an assist, in acting it's a supporting role, and in Bonneville speed racing it's a push truck. Whether the endeavor is scoring points, making movies or setting speed records, the stars of the show need a team behind them. When GM Performance Division engineers return to the Bonneville Salt Flats for Speed Week, they will have a supporting cast of customized vehicles behind them - both literally and figuratively.

This year's honor roll of one-of-a-kind support vehicles includes a HUMMER H3, a Chevy SSR, a Chevrolet Suburban and a pair of Chevrolet Silverado trucks.

The push truck is a venerable tradition at Bonneville. Top-speed runs require high gear ratios to achieve maximum velocity, but these ratios make acceleration from a standing start painfully slow. Many early Bonneville cars did not have transmissions, relying instead on high-gear-only direct-drive systems. Pioneer hot rodders ingeniously solved the problem of initial acceleration by employing a truck to push the race car up to speed before the driver engaged the clutch.

Today, push trucks continue to play an essential role in the specialized world of speed racing, providing the initial acceleration for the high-geared race cars. At the conclusion of a run, the push truck becomes a mobile workstation as the pit crew prepares the race car for the mandatory return run.

"Think of the Bonneville Salt Flats as a five-mile drag race," said Bobby Walden, crew chief of the record-setting So-Cal Speed Shop team. "If you push hard at the start of the run, you can continue to gain speed throughout the entire course. The push truck reduces the load on the race car's drivetrain, and it's a great ride when you're pushing the race car up to speed."

Headlining this year's supporting cast is a new HUMMER H3 that delivers authentic HUMMER style in a midsize package. Its orange-and-white graphics complement the Bonneville Student Project Cobalt that it will propel to speed on the salt.

With its rigid ladder-type frame, a powerful Vortec 3500 inline five-cylinder (I5) engine and a four-speed Hydra-Matic 4L60-E automatic transmission, the HUMMER H3 has the right stuff for push truck chores. The GM Performance Division team enhanced the H3's capabilities and appearance with custom touches.

The production Vortec 3500's technical features include dual overhead camshafts, variable valve timing and electronic throttle control. In stock trim, the five-cylinder Vortec 3500 produces 220 horsepower and 225 lb.-ft. of torque, outperforming many comparable six-cylinder engines. GM Performance Division boosted the customized H3's output to 350 horsepower and 350 lb.-ft. torque with the addition of a GM Powertrain-developed prototype turbocharger package.

The production Chevy SSR (shorthand for Super Sport Roadster) is like nothing else on the road. It's part roadster, part pickup and a thoroughly innovative expression of Chevy's performance heritage. The customized So-Cal SSR push truck adds another facet to the jewel of Chevrolet's Super Sport line, reinterpreting a classic hot rod design with state-of-the-art technology. Its distinctive red-and-white paint scheme evokes memories of the famous So-Cal Speed Shop push truck that adorned magazine covers in the '50s. A 6.0-liter Vortec small-block V-8 backed by a six-speed manual transmission provides ample power for fast acceleration in the thin air of Utah's high desert, while the 23.7 cubic foot capacity of the cargo bed delivers the functionality that's expected of a working truck.

"We worked hand-in-hand with ASC on the SSR project," said So-Cal Speed Shop president Pete Chapouris. "ASC performed the engine and transmission swap, crafted the gull wing bed cover and body modifications, and installed the red leather interior."

The So-Cal SSR converts quickly from street machine to push truck. Removable lights on the front panel conceal receptacles for the push bar. Retro styling touches include Budnik Muroc aluminum wheels (19-inch diameter front and 20-inch diameter rear), brushed aluminum trim, a louvered hood and a hand-formed aluminum rolled rear pan. The exterior rearview mirrors are based on a classic mid-'50s Chevy design. The push truck's cargo bed carries an aluminum floor jack, tools and a fire extinguisher.

"The So-Cal push truck combines classic hot rod styling with the contemporary technology of the production Chevy SSR to create a functional and totally unique race team support vehicle," said GM Performance Division Executive Director Mark Reuss.

The big guns in the GM Performance Division armada are a pair of Chevrolet Silverado pickups powered by Duramax diesel engines. A 2004 model has been outfitted with Gale Banks Engineering power enhancements, while a 2005 Silverado dually relies on a production 6.6-liter/310 hp Duramax 6600 for plenty of pushing power.

"These trucks have the torque we need to get the race cars up to 100 mph before we cut them loose," explained Chapouris. "The 2005 Silverado has four-wheel drive, and it's absolutely the best push truck available. The salt is so slippery that even the push trucks can spin their tires, so the extra traction of four-wheel drive is a huge advantage."

The final member of the support vehicle roster is a 1996 Chevy Suburban powered by a massive 605 ci big-block Vortec V-8 modified by Lingenfelter Performance. This monster motor produces 550 horsepower and 705 lb.-ft. of torque.

GM Performance Division's Bonneville support vehicles not only push race cars to record speeds, but also push the envelope of automotive design and performance.

General Motors Corp. (NYSE: GM), the world's largest automaker, has been the global industry sales leader since 1931. Founded in 1908, GM today employs about 317,000 people around the world. It has manufacturing operations in 32 countries and its vehicles are sold in 200 countries. In 2004, GM sold nearly 9 million cars and trucks globally, up 4 percent and the second-highest total in the company's history. GM's global headquarters are at the GM Renaissance Center in Detroit. More information on GM can be found at www.gm.com.