Bob Mannell's book shows a different design for the two blades (Appx F, PG F7, Design 9 and 11). The Ford Car Parts book makes these notations for the C6OA-C fan - "Integral A/C", "First 1000 units" and "used w/C4AZ-8A618-A" clutch. The dimensions are listed as 17 1/2 in dia and 2 3/8 in dia center hole. That was on full size Fords in 1965 and 66. The only reference for Mustang was the C6OE-G fan for 66 thru 68 (65 lists the same service P/N but no marking info), same dimensions as the -C.
Note: the -G was used on the 68 GT-350 so sell it on the Shelby forum and make a killing.
Jim