NOTICE: You will need to purchase an ECU and O2 Sensor to make this a complete kit.


An EFI system depends heavily on being supplied a clean and constant voltage source. The grounds of an electrical system are just as important as the power side. Our Holley EFI Harness Kit comes complete with the main harness, power harness and injector harness to support your primary system!


  • Harness Kit Includes; Main Power Harness, LS2 Main Harness & LSX Injector harness
  • Simple Installation
  • Works with HP or Dominator ECU's


SKU: 558-501
  • Brand Holley EFI
    Emission Code 4
    Harness Application LSX
    Product Type Harness Kit
    Part Number 558-501
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    This part is legal for sale or use on Racing Use Only Vehicles

    The following vehicles are considered Racing Use Only Vehicles:

    • Racing Use Only Vehicles are vehicles that are used exclusively for competition that are not registered and that may never be used on the street

    WARNING: It is against the law to install this part on an Emissions Controlled Vehicle