You might find a fan blade with more blades on it or more pitch. The flexblades work good if you get a good brand. A cheapy can throw a blade & do serious damage. Or if you run high RPM you wouldn't want to use one. I don't like fan clutches. The after market ones are not good. Some guys put an electric fan in front of the radiator with a manual switch. The position of the fan in the shroud can make a differtence also.
