This is the main EFI Harness that connects to all of the necessary factory sensors and related EFI sensors to run a Holley EFI system. There is an Early Gen III as well as a Late Gen III harness. The main difference between the early and late harnesses is within the connector for the crank and cam sensors. These changes were implemented across the truck and passenger car lines around 2007. There is not a firm change-over date. View the image gallery to determine the type of crank and cam sensors you have.


  • Take control of your Gen III HEMI with Holley EFI by controlling fuel and spark. Great for power upgrades as well as engine swaps.
  • Capable of tuning with power adders such as nitrous, superchargers or turbos and compatible with methanol and water injection
  • Harnesses are available to connect to a Gen III HEMI engine for the most advanced fuel and timing controls available
  • Each Harness fits and functions specifically for the Gen III HEMI engine platform
  • All wiring is TXL grade copper wiring with minimal weight in a small diameter, and can also withstand high temperatures
  • Factory style terminations provide a strong, secure connection
  • Connectors are OEM grade for a correct, positive fit
  • Each harness is routed through a split-loom braid for protection and also great looks