GM 10SI alternator with 6 & 12 mounting positions. 6.6" center to center mounting. High 140 amp, 1 wire easy to connect. Polished finish. Highest-quality neoprene-sealed bearings for long-life. Ultra low cut-in voltage regulators keeps the extra amps flowing in low idle situations. Exclusively-developed high-tech rotors and stators. Built with higher copper and steel content to deliver the greatest output with the best reliability.