Old Drag Racer Formulas: The "Q" Ratio or Factor??

Any old timers or old school racers remember something refered to as the Q" factor (or ratio) ?? Not sure if thats what its exactly called, I think you multiply your ET and MPH and you compare that figure to 1320, and how close or far (below/above) you are tells you about your setup? I believe I read about it on Grumpys Garage site but can't find anything anywhere about it, been a while
The one I use often to generally compare overall power vs efficiency-
1320 divided by 1/4mi mph = 1/4mi et potential
A well sorted car can generally come within a couple tenths of the formula.

Grant