Ultra Series GM 10SI Alternator

140 AMP - Cast Finish - 1 Wire

Deliver dependable power and show-quality style with the March Performance Ultra Series GM 10SI Alternator, designed with 6 and 12 o’clock mounting positions (6.6” center-to-center) for easy installation. This 140-amp, one-wire alternator provides strong, consistent charging with ultra-low cut-in voltage regulators for maximum output even at idle. Built with neoprene-sealed bearings, high-efficiency copper and steel internals, and a standard as-cast finish, it combines performance, durability, and precision craftsmanship. Backed by the March Performance Lifetime Warranty.