Improve your cooling system efficiency with this 1968-1969 Mustang 390 Big Block Fan Clutch Assembly from Scott Drake. The fan clutch engages the fan at low speeds when additional cooling is needed. At high speeds, the clutch disengages the fan, removing the load against the engine and allowing the engine to run more efficiently. This Fan Clutch is manufactured to ensure performance and durability. Although not concours correct, this closely resembles the original. 3.5 inches tall. Longer then original. Will not fit with thicker aftermarket radiators.