Double Letter Class Designators
By Flyin' Phil Elliott
Other then double A, the double letter classes came into being about 1966.
There is some confusion between dragster folk and "class" racers regarding double letters and advancing.
Originally, in the '50s, a car was classified cubic inches/weight with an asterisk (*). A blower advanced the car one class. So, a C/A with a 300 DeSoto and a blower was forced (pun intended) up to run B/A.
By the '60s, separate classes were created which stopped that habit -- and as stated above, the double-letter further defined those classes (AA/A, BB/A, CC/A, etc.). In some cases -- gas supercharged coupes and sedans for example -- the double-letters never caught on too well. These cars were still known as A/GS, B/GS, C/GS though there were a couple of years when the classes had the double letter PLUS the "S" (AA/GS, BB/GS, etc.)
In fuel dragsters, the class designations were not as clear from the grandstands but were based on cubic inches/weight, the way things were created. I don't have a '65 rulebook here to double-check the numbers. "A" might have had a maximum of 360 ci.
The thing that throws the monkey wrench into the works for history stat freaks is that none of the sanctions or tracks got together on these ci/weight rules.
As one example, the so-called "giant killer" injected SB Chevys, such as the Logghe-Marsh-Steffey machine, which often ran at 402 ci, were classified C/FD, B/FD, A/FD, and even AA/FD, depending on where they ran.
Also, teams that chose to run the 354 instead of a 392 Chrysler would be classified differently at various places. But keep in mind, these were for major races where classes were run. At most events, they all were thrown into Top Fuel.
Still, throw out the classifications, and there were many teams, like the Frantic Four, long proponents of the smaller Hemi, that felt the smaller, higher-revving capabilities helped them with various track conditions. Obviously, the tactic was a good one.