1956 Ford Fairlane with 312cc engine. Due to a gap issue in the original steel fan and the new aluminum heatsink, I bought a Spal 16 inch low profile fan 30100400 and a 16738 Derale 180 degree controller. The Derale controller only switched on the fan at over 220 degrees. The sensor and the fan worked great. Left idle for more than 30 minutes, and the temperature stayed between 170 and 175 degrees. Please note that it is not compatible with aluminum radiators. Don't expect much help from Derale's technical department.