Yet, Chevy engines put a new twist on this familiar theme. While some series have adopted rules that tightly define virtually every component and dimension in a racing engine, the USAC Midget Series offers engine designers the freedom to innovate. The opportunity to think "outside the box" is the kind of challenge that appealed to GM Racing engineers. Their innovative design of the new Chevy Midget racing engine is the product of imaginative thinking and advanced technology. Just the kind of thing any successful racing operation needs. Throw in some of those already-proven racing ideas and you've got yourself the foundation of a good motor.

Starting with today's version of a blank piece of paper-an empty computer screen-GM Racing engineers developed a package that is a departure from the engines traditionally used in Midget racing. The new Chevy motor has an innovative architecture that improves its combustion efficiency, enhances airflow and lowers the center of gravity. Advanced technical resources such as computational fluid dynamics and solid 3-D modeling used to design GM production engines were also used to develop the Chevrolet Midget racing engine.

Computational fluid dynamics (CFD) are used to determine the flow of liquids and gases inside the block and heads while it is still in the design stage and on the computer. Recent advancements with this relatively new form of computer work allow flows to be maxed out for efficiency and volume right from the start. Water flows, for one example, are so effectively controlled that they are now routinely held to a five degree variance anywhere in the engine.

Solid 3-D modeling helps in getting the products to the finish stage. Instead of making the first cast prototype pieces with new, handmade molds, the newly designed parts are first made of layers of a type of paper. Many of the growing pains of a new casting are eliminated by making these paper versions first while still in the design studio instead of the casting plant. Once engineers are happy with the paper versions, they can sign off for the first metal pieces to be made. Likewise, the casting plants are now working on a much faster turn around time than they have in the past. What used to take six months to bring about a part is now often delivered in less than three.

"The Chevrolet Midget racing engine represents another step in GM's continuous development of high-performance, high-rpm overhead-valve engines," says Tom Stephens, executive vice president, GM Global Powertrain and Global Quality. "Like the championship-winning Chevrolet R07 in the NASCAR Sprint Cup Series and the record-setting LS.7R small-block V-8 in the American Le Mans Series, the new Chevrolet Midget engine was designed and developed using many of the tools and technologies GM engineers employ to create exceptional production engines like the new 638hp LS9 small-block V-8."

The major components that define the Chevrolet Midget engine package-the cylinder block, cylinder head and certain ancillaries-will be available to all USAC competitors. Independent engine builders, such as Kistler Racing Engines of Fremont, Ohio, who supply the Chevy engines that power the two TSR entries, can then assemble engines using remaining internal and external components from their preferred suppliers.

"Many of the aftermarket engines currently racing in the Midget series are based on the four-cylinder Chevy II engine produced in the '60s," explains GM Racing director Mark Kent. "Others are essentially one bank of a conventional V-8 engine. We took a different approach to bring innovative technology to the series while respecting a racing heritage that reaches back to the '30s. We've also incorporated lessons learned in designing and developing race-winning engines for NASCAR, ALMS, and NHRA competition. By harnessing GM's technical resources to create a brand-new Midget racing engine, we're putting more Chevy into the cars that wear bowties on the racetrack."