First established in the United States after World War II, this type of racing was early-on characterized by its participants' modification of passenger cars in pursuit of higher speeds, hence the name.

[1] (In June 1949, NASCAR organized its first "strictly stock" later model car race at Charlotte, North Carolina, which evolved into its well known premiere division.)

Each sanctioning body has their own set of guidelines provided in an annual rule book and their own registration fees.

Drivers sit on the left side of the car, and most of the time will have some type of small plastic windshield in front of them.

Asphalt Modifieds are most popular in the Northeast but can be found from Florida to Texas to Michigan under different sanctioning bodies, as well as unsanctioned local classes.

[3] The Midwest Modifieds Tour started in 1989 as the E-Mod Series at Mount Lawn Speedway near Indianapolis IN.

The series changed hands for 2017, from ICAR to NSTA, after being purchased by John Robbins (nephew of the former ASA pioneers) from Dave Muzillo.

The series also had previously made forays into road racing with stops at Watkins Glen International in New York.

[7] Drivers like Bobby Allison and Red Farmer started in the NASCAR Modified series, which was popular both in the south and the Northeast.

Many NASCAR Sprint Cup drivers have come from this series, including Ryan Preece, Jimmy Spencer, Geoff Bodine and Steve Park.

[9] Harpell subsequently purchased the historic Race of Champions, and rebranded the series upon creation of a separate Dirt Modified Tour in 2005.

[14] Race promotors, drivers and car builders who focused on the dirt tracks in northeastern U.S. and southeastern Canada, became eager for standardized rules.

By 1967 the limitations had evolved to include small block engines, a single carburetor and pump gasoline.

[15][16] Looking to differentiate the Sportsman as a truly separate class, and expecting spectators to relate better to newer model cars, NASCAR dropped the pre-war coupes and sedans for the 1968 season, substituting the Late Model Sportsman Series (later to become the Xfinity Series) with 1955 and newer bodies.

[16] Several non-sanctioned venues in the Northeast continued to run a combined support class with old and new bodied sportsman.

Propelled by the strong economics of southeastern Canada's metropolitan areas, the "small blocks" became the premiere class in the St. Lawrence River Valley.

The new division increased the gate revenues at the pit window, and created new customers for modified teams to sell their used cars to.

Although there may be some cost saving restrictions on the cars, the primary limitation rests with the experience level of the drivers.

[22] The former DIRT big-block (and small block) modified series has seen many changes in their car designs since the 1970s, but the competition and will to win has remained the same.

Notable drivers having competed in DIRTcar modifieds include Bobby Allison, Tony Stewart, Andrew Ranger, Dave Blaney, Carl Edwards, J. J. Yeley and David Reutimann.

While modified racing remained popular on the east coast, varieties of the "strictly stock" / "late models" became the primary class in other parts of the country.

Organized in 1915, the International Motor Contest Association (IMCA) is the oldest racing sanctioning body in the US.

[25] It has become one of the most popular dirt racing classes due to its simple design, light-weight, high power, and ability to adapt to varying track conditions easily.

Most IMCA-style classes also boast a "claim rule", wherein a racer may buy a competitor's engine for a small amount of money (usually around $500).

The Afco KidModz appear the same as the others, but sport full tube chassis, and by rules, have to have Ford 2300 cc inline 4-cylinder engines.

This relatively inexpensive (when compared to their "adult" counterparts) racing series is aimed at attracting younger drivers as an entry-level class.

These outlaw modifieds sport full tube chassis, and bodies that look like the Advanced Auto Parts Super DIRTcar racers, with the exception of the sprint car-like wing affixed to the roofs of the cars.