Holley Harnesses

The Terminator X offers an advanced engine management solution specifically tailored for the formidable 7.3-liter Godzilla engine. Designed to unlo...

This Harness is required with HP or Dominator ECUs. Includes, 13' long, 10 AWG main power harness, Qty. (2) 3/8" ring terminals and shrink tube (no...

The Terminator X offers an advanced engine management solution specifically tailored for the formidable 7.3-liter Godzilla engine. Designed to unlo...

Introducing Coyote Twin Independent Variable Cam Timing Control from Holley EFI! Do you have a coyote crate engine going in your dream car? Is your...

"Big Wire" Sub Harness- pre wired with 12ga power and grounds, for optimal performance!

The unterminated main harness comes with both J1A and J1B connectors full terminated with 15' of flying lead wiring. Features: 15’ long flying l...

Introducing EFI Engine Connector Kits – From Holley EFI. With the latest addition to our ever-expanding Wiring Shop, our goal was to provide you wi...

Ford V8 Injector Harness for Ford USCAR / EV6 style Fuel Injectors (Evenly Spaced)

This wiring harness interfaces a Holley EFI ECU to a 4V Ford Modular engine. It is meant to be used in conjunction with an injector harness, a coil...

This wiring harness interfaces a Holley EFI ECU to a 2V Modular Ford engine. It is meant to be used in conjunction with an injector harness, a coil...

Introducing the Holley EFI Programmable 8 Channel Injector Driver Module. The ultimate solution for methanol burning engines that require a large s...

This harness provides a plug and play upgrade solution for those seeking to convert to Coil-On-Plug. Additionally we have pre-installed a Power Tap...

V8 over Manifold, Bosch Style Connector Harness for Avenger EFI, HP EFI & Dominator EFI

Unterminated Vehicle Harness For Digital Dash

Terminated Vehicle Harness For Digital Dash

Service replacement digital dash harness. Features: CANBus Connector Wiring USB Connector Wiring

The Holley EFI Can Adapter/Power Harness adapts two pin Holley main harness CAN connectors to new style 4 pin CAN devices.

I/O Adapter w/Terminated Vehicle Harness Features: Provides ten addiitonal inputs/outputs to the 7" digital dash Brings out connections to a wat...

The Holley EFI Can Adapter/Power Harness adapts two pin Holley main harness CAN connectors to new style 4 pin CAN devices.

I/O Adapter w/Unterminated Vehicle Harness Features: Provides ten addiitonal inputs/outputs to the 7" digital dash Brings out connections to a wa...

Introducing Coyote Twin Independent Variable Cam Timing Control from Holley EFI! Do you have a coyote crate engine going in your dream car? Is your...

Coil Harness for 2011 to 2015 Ford Coyote (5.0L) Engines

Introducing Coyote Twin Independent Variable Cam Timing Control from Holley EFI! Do you have a coyote crate engine going in your dream car? Is your...

Introducing Coyote Twin Independent Variable Cam Timing Control from Holley EFI! Do you have a coyote crate engine going in your dream car? Is your...