1987 Ford F-350 Engine: 4.9L L6; Reverse Rotation; Standard Duty Thermal Fan Clutch;. 1988 Ford F-350 Engine: 4.9L L6; Reverse Rotation; Standard Duty Thermal Fan Clutch;. 1989 Ford F-350 Engine: 4.9L L6; Reverse Rotation; Standard Duty Thermal Fan Clutch;.