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1981 GMC Sierra – Gateway Classic Cars – San Antonio / Austi…

GatewayClassicCarsJuly 27, 2025Last Updated: July 27, 2025

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Gateway Classic Cars of San Antonio/Austin is happy to offer this LS swapped 1981 GMC K15 High Sierra 4×4! Introducing the 1981 GMC Sierra, an iconic classic that blends the charm of yesteryears with the power of modern LS technology. This vehicle is a stunning display of both style and performance, featuring a sleek black exterior that nicely complements its black & gray cloth interior. Powered by a 5.3L LS initially sourced from a 2003 Silverado that is now fitted with a FAST 102 intake & fuel rails, a Jet 75mm Power Flo throttle body & a Spectre cold air intake that is HP tuned & hooked up to a 4L60E transmission, a 12 bolt rear end with 3.73 gearing and factory transfer cases. This build was completed by the previous owner who was an ASE certified tech & no corners were cut. Thanks to the custom made ECM and harness, all the factory gauges work as they should and the dual 16 gallon tanks are both fitted with Corvette electric fuel pumps, so the fuel gets where it need to be! This also has a true custom H-pipe exhaust set up & sounds incredible. This K15 is sitting on some factory GMC 15″ alloy wheels & Cooper Discovery AT rubber giving it an incredible stance and a newer steering gear box keeps it tight with the steering, giving you “better than factory” control. The interior carpets were recently replaced with OEM carpets with underlay, newer headliner & a seat sourced from a later model Chevy. This 1981 GMC is definitely ready to be enjoyed just as it sits!