The 410ci sprint car is an open-wheel, open-cockpit race car designed exclusively for short oval competition. The car weighs approximately 1,400 pounds including the driver and is powered by a naturally aspirated, methanol-injected overhead-valve American V8 engine displacing 410 cubic inches (6.7 liters). Power output exceeds 900 horsepower, producing a power-to-weight ratio that surpasses contemporary Formula 1 cars. The cars can reach speeds in excess of 160 miles per hour depending on track layout and mechanical setup.
Sprint cars carry both a large top wing and a smaller front wing, which generate aerodynamic downforce to improve traction on dirt surfaces. The wings also serve a safety function: the added downforce reduces the likelihood of a car becoming airborne, and when cars do flip, the wing contacts the ground first and absorbs impact energy by crumpling or breaking away. Wings became mandatory at Knoxville Raceway in 1982.
The drivetrain is unconventional by road-racing standards. Sprint cars have no transmission, only an in-or-out gearbox and a quick-change rear differential for occasional gear-ratio adjustments. There is no electric starter and no conventional electrical system beyond the ignition magneto; cars require a push start from a quad or truck. The direct-drive system can be engaged or disengaged from the cockpit.
Knoxville Raceway is a semi-banked half-mile dirt oval located at the Marion County Fairgrounds. Weekly racing at the track features 410, 360, and Pro Sprint classes each Saturday from April through September. The 410 class is the headline division, attracting the top winged sprint car pilots in the country.
Marion Robinson, appointed race promoter in 1956, guided the track's evolution from stock cars through modifieds and supermodifieds to sprint cars. He created the Knoxville Nationals in 1961, an event that began as a two-day, $5,000-purse gathering and has grown to a payout approaching one million dollars. The Nationals are held each August and stand as the most important sprint car event in the United States.
The all-time leader in 410 feature wins at Knoxville Raceway is Danny Lasoski of Dover, Missouri, with 112 feature victories. The record for consecutive weekly wins belongs to Doug Wolfgang of Sioux Falls, South Dakota, who won 10 straight races to open the 1977 season and claimed 13 of 18 events that year, including the Nationals.
The World of Outlaws (WoO), founded by Ted Johnson in 1978, is the premier traveling series for 410ci winged sprint cars. The series runs events throughout the United States from February through November, and Knoxville Raceway is among its most celebrated stops. WoO cars use 15-inch wide right-rear tires and mechanical fuel injection. A pre-race tradition unique to the series has cars line up four-wide on the front straight as a salute to fans before the start of the A-main feature.
The All Star Circuit of Champions (ASCoC), founded in 1970, also sanctions 410ci sprint car races and competes across Ohio, Indiana, Pennsylvania, Michigan, Illinois, Wisconsin, New York, and Florida. The Knoxville 410 class regularly draws competitors from both series in addition to regional and local specialists.
The 410ci sprint car at Knoxville occupies a unique place in American motorsport. It has served as a development path for numerous drivers who reached the highest levels of professional racing, including Indianapolis 500 winners A.J. Foyt, Mario Andretti, Johnny Rutherford, and Al Unser Sr., as well as NASCAR Cup Series champions Jeff Gordon, Tony Stewart, and Kyle Larson. The National Sprint Car Hall of Fame and Museum, located in Knoxville, Iowa, preserves the history of both winged and wingless sprint cars and is a testament to the class's enduring cultural importance in American grassroots motorsport.