Within the dirt modified world, the "big block" designation distinguishes cars running larger-displacement V8 engines from the small block (or 358 modified) category that uses 358 cubic inch engines. Both variants share the same center-steer open-face chassis architecture and dirt oval racing context, but the big block class represents the highest level of performance and is the primary touring class for the sport's elite drivers.
The Super DIRTcar Series, the national touring championship for big block modifieds, was founded in 1972 by Glenn Donnelly as a series of qualifier events for the inaugural Super Dirt Week at the New York State Fairgrounds in Syracuse, New York. It became a formal points championship in 1974, with Will Cagle winning the first title over Buzzie Reutimann.
Big block modified engines are limited to a maximum of 467 cubic inches and run on VP Fuels racing gasoline, delivered via a four-barrel Holley carburetor rated at 950-1050 cfm. Horsepower ranges from 650 to 800, with engine speeds between 7,000 and 8,300 rpm and compression ratios of 13:1 to 14.5:1. A two-speed transmission with one reverse gear and a quick-change rear end transmit power to the rear wheels. The belt-driven dry-sump lubrication system holds approximately 13 quarts of oil.
The chassis is a steel space frame constructed from 1018 or 1020 steel, with a wheelbase between 106 and 110 inches and a minimum track width of 74 inches. Minimum weight including the driver is 2,500 pounds. Suspension uses coil-over setups at all four corners — coil springs at the front, coil springs or torsion bar at the rear. Four-wheel hydraulic disc brakes operate without power assist, and power steering is standard.
Cars run Hoosier Racing Tires, with the right rear tire circumference specified at 92.5 inches. Ground clearance is approximately 5 inches at the front and 6 inches at the rear, with a 2.5-inch minimum.
At a one-mile oval like the old Syracuse venue, big block modifieds have been recorded at approximately 160 mph.
The Super DIRTcar Series is the primary competition platform for big block modifieds. After its 1972 founding, the series developed a corporate following and television coverage throughout the 1980s and 1990s, with sponsorship from Schaefer Beer, CRC Industries, Sun Country Cooler, US Smokeless Tobacco, and Advance Auto Parts at various points. World Racing Group (then Boundless Motorsports) acquired the series in 2003.
The series races primarily on dirt ovals in the northeastern United States and Canada, with events also scheduled in Florida and North Carolina. Super Dirt Week, the series crown jewel, moved from the New York State Fairgrounds mile in Syracuse to a dirt-covered Oswego Speedway in Oswego, New York in 2016 after the Syracuse venue was demolished. The Billy Whittaker Cars and Trux 200 at Super Dirt Week offers $50,000 to the winner, one of the largest single-race prizes in dirt modified racing.
Other major events on the Super DIRTcar Series schedule include the DIRTcar Nationals at Volusia Speedway Park in Florida, the Hall of Fame 100 at Weedsport Speedway, Mr. DIRT Track USA at Lebanon Valley Speedway, and the World of Outlaws World Finals at Charlotte Motor Speedway.
Brett Hearn is the all-time wins leader in Super DIRTcar Series competition with 141 victories, and holds records for the most seasons with at least one win (32) and the most consecutive seasons with at least one win (22). He also shares the single-season wins record of 10, matched by Billy Decker in 2008 and Matt Sheppard in 2016. Alan Johnson holds the consecutive wins record with five straight victories in 1983.
Matt Sheppard has won the most Super DIRTcar championships overall with ten titles. Alex Yankowski holds the record as the youngest race winner in series history at 17 years old.
Alongside the big block class, the 358-Modified category — also organized under the DIRTcar umbrella — provides a parallel ladder using 358 cubic inch engines. The class originated from NASCAR's old Sportsman division, which was revised in 1968, and is particularly strong in the St. Lawrence Valley, Hudson Valley, and Twin Tiers regions of New York and Pennsylvania. The Mr. DIRTcar 358-Modified championship, introduced in 1983 as the Mr. Dirt 320 Modified Championship, tracks the best 358 competitors across weekly home-track events, with the 358 engine class introduced to the championship in 1985.