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. The 170 amp unit comes equipped with an OEM diameter pulley, making it perfect for high RPM and racing use while still providing great output at idle. THIS UNIT COMES SELF EXCITING IT HAS NO PLUG AND NEEDS NO CONTROL HARNESS. . .ITS COMPACT DESIGN AND SIDE OUTPUT MAKE THIS A GREAT OPTION FOR LS ENGINE BUILD APPLICATIONS USING GM TRUCK STYLE MOUNTING BRACKETS!