Ultra Series GM 10SI Alternator

140 AMP - Black - 1 Wire

Upgrade your build with the March Performance Ultra Series GM 10SI Alternator, engineered for reliability, efficiency, and style. Featuring 6 and 12 o’clock mounting positions (6.6” center-to-center) and a simple one-wire hookup, this 140-amp alternator delivers strong, steady charging with ultra-low cut-in voltage regulators for dependable output even at idle. Built with neoprene-sealed bearings, high-efficiency copper and steel internals, and a sleek black finish, it’s designed for long-lasting performance and modern appeal. Backed by the March Performance Lifetime Warranty.