NASCAR star Carl Edwards is leaning against a cabinet in his team's transporter at Pocono. Qualifying is right around the corner, but Edwards has dirt on his mind. "I learned the most about how to run a team, how to build a car, how to maintain a car, and how to compete when I ran Modifieds," he says proudly.

Edwards is one of a growing number of racing superstars to make it to the big time by taking the dirt road. But on this dirt road, you turn left four times in one third of a mile at better than 80 mph while zig-zagging through rush-hour-like traffic with dirt, stones, and the occasional car part flying right at you.

This dirt road is the turf of the International Motor Contest Association, commonly known as the IMCA.

Close to 7,000 dirt trackers call the Iowa-based sanctioning body home. They race anywhere and everywhere, from Brewerton Speedway in New York, to Atomic Motor Raceway in Idaho, and at more than 120 other racetracks in between. That makes the IMCA one of the most prolific sanctioning bodies in the world.

The IMCA is also the oldest active sanctioning body in the United States, predating NASCAR by some 33 years. Founded in 1915, the IMCA grew rapidly and was sanctioning more races in the United States than any other organization by the late '30s.

For decades, the IMCA was known for its Sprint Cars. But in the '70s, the sanctioning body fell on hard times. The IMCA was teetering on the brink of bankruptcy when Hawkeye Racing News publisher Keith Knaack bought it and began a retooling process that would shape local dirt track racing for years to come.

Knaack was a pioneer and an innovator who had a unique vision of motorsports. It was a simple concept: Keep racing affordable for the grassroots racer. In the late '70s, Knaack felt that Late Model racing in the U.S. was on the decline. His solution was the introduction of a Modified division that would bridge the gap between the low-buck Hobby Stocks of the day and the more expensive Late Models. Ironically, the cost-effective Modifieds became the sanction's marquee division and would grow to become the largest class of race car in the United States.

Health issues forced Knaack out of the day-to-day operations, and his longtime employee Kathy Root took over the presidency of the sanctioning body in 1990. Four years after Knaack's death in 1992, Root purchased the IMCA from the Knaack family.

Staying true to Knaack's philosophy, Root and her son Brett have built IMCA into one of the premiere sanctioning bodies in the country. Under their direction, IMCA has grown to encompass eight divisions racing across five different regions. From California to New York, the list of IMCA-sanctioned tracks tops out at 130 in 27 states, more than double the number of tracks in NASCAR's Weekly Racing Series.

Each Labor Day, Boone, Iowa, transforms into something surreal. Like Sturgis, South Dakota, in early August, Boone experiences a population explosion rivaled by few other events. Race fans, thousands of them, descend upon the small Midwest town. They travel from as far away as the East Coast and as close as the next county. They have come to Boone Speedway for six days of the best dirt racing action in the country-the IMCA Speedway Motors Super Nationals. Dubbed "America's Racin' Vacation," it is IMCA's version of Daytona Speedweeks. But instead of 60 racers in two divisions and five races, this event draws well over 700 of the top dirt drivers who race in dozens upon dozens of races for six different championships.

Guys such as Nebraska's Johnny "The Jet" Saathoff, the four-time IMCA National Modified Champion; David Murray Jr., the Oberlin, Kansas, driver who tops the all-time feature wins list with over 350 victories; and the Hall brothers from Minnesota make the annual trek south to race in cars older than some IMCA competitors.

The mix of drivers and talent at the Super Nationals is one thing that makes the week so special. Another is the qualifying format. On the final day of competition, each division crowns a champion at the end of a single feature race. To get into that feature, drivers compete in a series of qualifying races held over multiple days. There is also an All Star Invitational: 10 drivers, 10 laps, $1,000 to win. And fans get to vote for the drivers who get those coveted 10 spots via the IMCA Web site.

The qualifying format, the invitational, and the sheer scope of the event add up to a solid week of non-stop, dirt-spewing, alcohol-burning action for thousands of race fans.

The IMCA's success is due in large part to its dedication to its mission statement: "IMCA is based on enforcing fair and consistent rules that promote affordability as the foundation of racing in America."

Any IMCA racer will tell you that the rules package is one of the most attractive in motorsports. "Not many classes of cars can say that they can race anywhere in the country and be legal," says New York native and '03 Can-Am Speedway Track Champion Rob Keller Jr.

It is that freedom of travel and the cost-effectiveness of the series that have earned IMCA a steadfast following among dirt racers. Keller estimates that you can run a full season of IMCA Modifieds on about $12,000 to $14,000, and that's for a Top 10 car. Go west to Nevada and that figure can drop to $10,000.

"You can buy a 1- to 2-year-old rolling chassis for about $6,500. Figure $1,200 for a transmission and then realistically $2,000 to $3,000 for an engine," says Keller. "The remainder is tires, gears, and other normal racing expenses."

Two grand for an engine seems cheap, especially when you consider a DIRT Northeast Modified motor can cost as much as $35,000. Racers like Keller are reluctant to spend a lot of money on their engines because of IMCA's claim rule, a cost-control mechanism that prevents spending gobs of money on motors. However, the claim has morphed into what many call a grudge tool. "Unfortunately that [grudges] is mostly what it is used for," says Keller who has been claimed at least three times in previous years.

In response, IMCA instituted an exchange addendum to its claim rule last year. Now, any claimed driver has the option of accepting $525 cash for his or her motor or exchanging engines with the claiming driver.

"If you have to give up your engine to claim the other guy's, then you darn well better be sure that the reason he's kicking your butt is because he has a better engine in there and not just a better handling car or better setup," says Keller.