I just arbitrarily grabbed my old 70 shop manual, and it shows a variation of between 16 1/2 and 19 PINTS (not quarts). So as much as 9 1/2 quarts, and of course those figures were for full size TQs and stock size pans
so u figure an 8 inch converter, deep pan, outboard trans cooler...and i'm still probably 2-3 quarts overfilled?....would explain why FootBrake stall went down...maybe the extra fluid is preventing the weights from slipping from having to slosh through all that fluid.