Next to NASCAR and FIA, USAC might be the best-known sanction in the world. The Speedway, Indiana-based organization has a storied history with quite a story. The United States Auto Club, or USAC, was formed when the American Automobile Association (AAA) withdrew from auto racing following the infamous 1955 24 Hours of LeMans disaster in which 82 people were killed when a car crashed into the crowd. USAC effectively took AAA's place as the top sanction in the world for what they termed Championship automobile racing.

From 1956 to 1979, USAC sanctioned the United States National Championship; a title won by world-renowned drivers such as A.J. Foyt, Mario Andretti, Bobby Unser, Al Unser Sr., and Tony Bettenhausen. But in those days the sanctioning body had a reputation of unpredictable rules enforcement, which eventually led to bad blood between the sanction and the car owners and drivers. It spilled over in 1979 when the lion's share of the teams competing in USAC's Championship Series broke away and formed their own organization, Championship Auto Racing Teams, or CART.

While a lawsuit ensued over which organization had the right to use the word Championship, the fight eventually settled down. For the next 18 years, USAC sanctioned the Indy 500, as it had since 1956, while CART kept the race on its annual schedule.

The peaceful coexistence ended in 1996 when Tony George started the Indy Racing League and split with CART, decimating big-time open wheel racing in the U.S. USAC became the sanctioning body for the IRL, but that only lasted until the 1997 IRL race in Texas. At that event, USAC officials errantly scored Arie Lyendyk two laps down, when in fact he won the race. The debacle, which included A.J. Foyt slapping Lyendyk in Victory Lane, was USAC's final racing event for the IRL.

USAC weathered its exodus from big-league open wheel racing just fine. As far back as the mid-'50s, USAC sanctioned the National Midget Series and the Sprint Car Series. In fact, they have crowned a champion in each of those series since 1956. They also added the Silver Crown Series in 1971. Originally, these series were feeders for the Championship Series. Today they are some of the most coveted championships in open wheel racing, and arguably, one of the best paths to the upper echelon of motorsports. Six of the last 10 NASCAR Nextel Cup Championships have gone to former USAC champions.

One of the reasons that you see a high number of USAC vets in the upper levels of NASCAR has to do with talent.

"You learn to be versatile racing in USAC," says four-time USAC Champion and defending Nextel Cup Champion Tony Stewart. "You race a 900-pound Midget, a 1,200-pound Sprint Car, a 1,400-pound Silver Crown Car on dirt and asphalt-three different types of cars on two different surfaces at tracks ranging from half-mile up to mile and a half. Because you have to constantly adjust to each one, it doesn't get you in a habit or pattern.

Habits and patterns can be bad and are easy to get into when you race just one type of car. The versatility that Stewart spoke of is the very reason that Nextel Cup owners continually look to USAC for their next superstar.

The bulk of today's USAC is made up of four series, each racing a different type of car on dirt and pavement. The Silver Crown cars are the big dogs running on tracks 1 mile and larger, while Sprint Cars usually race on tracks 5/8 mile and smaller. Midgets are the oldest type of USAC racer with designs dating back to the '30s, while the Ford Focus Midgets are the newest ones dating back to 2002. Let's take a closer look at each one.

There are two types of Silver Crown cars: a dirt version and a pavement version. The dirt car looks very similar to a Sprint Car but is actually much bigger. Tucked in the 96-inch wheelbase is a fuel tank that holds 75 gallons of methanol-plenty of juice to finish a 100-mile race sans pit stop. Silver Crown cars get their muscle from a 355ci American production-based engine that produces over 700 hp. Put that in a 1,500-pound car and you have a monster that is super quick and wildly nimble.

Switch over to pavement and you have a radically different animal. Introduced just last year, the pavement Silver Crown cars look like nothing you have seen before. It's as if a Sprint Car fell out of the sky and landed on top of a WKA Kart that had been injected with a massive dose of Balco's best steroid cocktail. The car and its design serves only one purpose: to launch USAC into the future and back onto the world stage.

"We wanted to take USAC open wheel racing to major venues across the country," explains President/CEO of USAC, Rollie Helmling. "We would never have had the opportunity to do that without the new-generation cars."