Whenever a Mustang's engine is modified to make more power, the demand on the cooling system increases. More power means more heat, and the limitations of the stock Mustang cooling system, with its engine-driven fan, can soon become apparent. A modern electric fan is one answer to overheating woes. The Spal electric fan is a low-profile unit so interference with pulleys isn't a problem. It includes a complete electrical harness with a relay and detailed instructions. While the fan is thermostatically controlled, it can also be equipped with a manual override. For air-conditioned cars, the fan turns on any time the A/C is activated. A built-in shroud to channel airflow is a considerable improvement for those with an open radiator on all sides. Even better, an electric fan frees up the power that was used to drive the mechanical fan.