For use originally on 1967 289 engines with California emissions (All 1967 DSO 52 and 53 Mercury Cougars), and without factory air conditioning. With extra cooling (20 inch wide radiator).
3 sheave pulley (three fan belts), with pulleys having diameters of 4-7/16 inches and 5-7/8 inches.
Ford casting number C6OE-8509-A, was probably an ink stamp. These pulleys were made using a double sheave C6AE-8509-A pulley with a second smaller pulley welded on.