Step-by-Step Install Instructions

Looking for an Affordable, In Stock, Plug and Play wiring harness for your LS Swap? PSI sells Standalone Wiring Harnesses for GM Gen II, III, IV, & V LS/LT based engines and transmissions. These harnesses include the Gen II LT1/LT4, Gen III (24x) LS1/LS6 and Vortec Truck Engines as well as Gen IV (58x) LS2, LS3, LS7, & Vortec and GEN V LT / ECOTEC3 Engines. All PSI Harnesses are Made in the USA and are 100% Computer Quality Tested. In addition to wiring harnesses, PSI carries Holley Products, Vintage Air A/C, Dakota Digital Gauges, HPTuners and PCM programming, Fuel Pump Kits, Engine Sensors, Extension Harnesses, Replacement GM connector pigtails and a complete line of hardware to complete your conversion!

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Step-by-Step Install Instructions

HAR-G3CA/G3CM

HAR-G3WA/G3WM

HAR-G4WA/G4WM

HAR-HOLLEY

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