EFI Harnesses

Holley wiring harnesses let you adapt your EFI system without the hassle of replacing your entire kit. Whether you're switching from drive-by-cable to drive-by-wire, updating transmission control, or changing injector types, we've got you covered with easy-to-install solutions designed to grow with your build. Engineered for performance and reliability, Holley harnesses deliver the clean, factory-quality wiring your project demands—every step of the way.