LS Gen3 24x Standalone Harness – Swap Specialties Home / LS 24x and 58x / Harnesses and PCM's / LS Gen3 24x Standalone Harness. LS Gen3 24x Standalone Harness $ 495. Swap Specialties 24x Standalone wiring harness for GM Gen3 4.8, 5.3, 5.7, and 6 Engines have proven to be the best harness on the market today. Use the selections to build your custom harness, or feel free to give us a Direct-Fit Custom GM LSx/Vortec/LTx Engine Wiring Harness Our Direct-Fit custom wiring harnesses are plug-and-play, custom built, and designed specifically for your project utilizing a 94-97 LT1/4 or 97-up LSx or Vortec small block. Each harness is built from scratch specifically for your engine and vehicle combination.