A      1898-1915 (except Model T Fords) including one and two cylinder steam and          electric cars.
B-1   Brass radiator Model T Fords
B-2   Steel radiator Model T Fords
C-1   1928-1931 Model A Fords, open
C-2   1928-1931 Model A Fords, closed
D      1916-1925 cars (except Model T Fords & Classics) 
E       1926-1931 cars (except Model T & Model A Fords and Classics)
F-1    1932-1938 cars, open (except Classics)
F-2    1932-1938 cars, closed (except Classics)
G-1   1939-1942 cars, open (excepts Classics)
G-2   1939-1942 cars, closed (except Classics)
H      1943-1945 vehicles, including military (except motorcycles and Classics)   
I-1    1946-1954 cars, open (except Classics)
I-2    1946-1954 cars, closed (except Classics)
J-1    1955-1963 cars, open (except Classics)
J-2    1955-1963 cars, closed (except Classics)
K-1    1964-1972 cars, open
K-2    1964-1972 cars, closed
L-1    1973-1981 cars, open
L-1A  1973-1981 cars, closed
L-2    1982 to 25 yrs old, cars, open
L-2A  1982 to 25 yrs old, cars, closed
M-1   Trucks to 1942 (Including Ranchero/El Camino)
M-2   Trucks 1943-1958 (Including Ranchero/El Camino)
M-3   Trucks 1959 to 25 yrs old (including Ranchero/El Camino)
N       Speedsters and race cars to 25 yrs old
N-1    Sports cars-Special Interest to 25 yrs old 
N-2    Chevrolet Corvettes, 1953-1967
N-2A  Chevrolet Corvettes, 1968 to 25 yrs old
N-3    Ford Thunderbirds, 1958 to 25 yrs old
N-3A  Ford Thunderbirds, 1955-1957
N-4    Chevrolet, 1955-1958
N-5    Ford Mustangs to 25 yrs old
N-6    Ford Falcons to 1970
N-8    MG's to 25 yrs old
N-9    Triumphs to 25 yrs old
O-1    Motorcycles to 1936
O-2    Motorcycles 1937-1950
O-3    Motorcycles 1951 to 25 yrs old
O-4    All motorized bicycles/mopeds and motor scooters to 25 yrs old

CLASSICS (as defined by MOTAA)
P-1   1921-1936 Classics, open
P-2   1921-1936 Classics, closed
Q-1   1937-1948 Classics, open
Q-2   1937-1948 Classics, closed
R-1   1949-1959 Classics, open
R-2   1949-1959 Classics, closed