A1 – Original Stock 0 – 1959
A2 – Original Stock 1960s
A3 – Original Stock 1970s – 1980s
A4 – Original Stock 1990 – Present
B1 – Street Rods Pre-1949
B2 – Street Machines 1950s – 1960s
B3 – Street Machines 1970s – 1981
B4 – Street Machines 1982 – Present
C1 – Camaros/Firebirds 1967 – 1981
C2 – Camaros/Firebirds 1982 – 2002
C3 – Camaros/Firebirds 2010 – 2015
C4 – Camaros/Firebirds 2016 – Present
D1- Mustangs 1964 – 1978
D2 – Mustangs 1979 – 2004
D3 – Mustangs 2005 – 2014
D4 – Mustangs 2015 – Present
E1 – Challenger/Charger 1966-1987
E2 – Challenger/Charger 2005 – Present
F1 – Truck Stock Pre-1954
F2 – Truck Stock 1955 – 1972