The S series of 6 phase alternators offers incredible output in a compact and durable package. Highly efficient, these units use less horsepower than conventional 3 phase alternators. 12 diodes, twin rectifier plates and outstanding airflow ensure long service life, even in severe conditions. This unit features an OEM 2.6" diamter pulley, making it great for racing applications using the stock diamter crankshaft pulley. If changes have been made to the diamter of the crankshaft pulley on the engine, please contact a sales associate for assistance with calculating pulley ratio.