EFI Connection Harnesses

Our own stand-alone, plug and play, and custom engine harnesses for Holley EFI systems are a value difficult to match. With production tooling, ultrasonic splices, genuine components, and wire color correct construction, you'll have no issues using our products with other Holley brand components.

Holley Brand Harnesses

Genuine Holley® brand harnesses for Holley EFI systems.

Adapter & Extension Harnesses

Make quick work of installing your Holley engine harness by using our sensor adapter and extension harnesses. These harnesses make Holley's universal main harnesses application specific.