Street. Track. Everything between.
07 3276 7829
Your garage Find parts for your vehicle Select year, make and model to narrow your search.

Holley Terminator EFI Wiring Harnesses 558-420 Fuel Injection System Harnesses, EFI, Auxiliary Input/Output Harness, EFI, Gains 4 Inputs/1 Output, Each

Holley Terminator EFI Wiring Harnesses 558-420 Fuel Injection System Harnesses, EFI, Auxiliary Input/Output Harness, EFI, Gains 4 Inputs/1 Output, Each

A$132.57
IN STOCK! Est Ship 4-7 days. In stock at 2 locations (more than 10 available)

Added to cart

We accept
American Express
Mastercard
Visa
PayPal Checkout
Direct Deposit
Afterpay
Apple Pay
Google Pay
Zip Pay

Description

EFI Wiring Harness - Input / Output - Holley Terminator EFI - Each


Data: v2 - Desc: v4.2 - Upd: 2026-11-08 02:14:53

Data: v4.2 - Upd: 2026-11-08 06:35:10

Features

Vehicle Compatibility and Return Conditions.

This item was designed and engineered in the USA for US domestic vehicles. OBD tools, ECUs, dongles, programmers, and tuners may have limited compatibility with vehicles outside the USA due to regional differences in emission standards and system configurations. Some features and functionality may vary depending on the vehicle and location.

Some electronic tuning devices and programmers require activation, registration, or pairing with a specific vehicle’s VIN (Vehicle Identification Number). Once activated or paired, these devices may become permanently associated with that vehicle, restricting or preventing their use on another vehicle, resticting our ability to offer returns or exchanges.

Please review the product details and images to ensure it meets your needs. For clarification or assistance, feel free to contact a StreetFX agent. Note: Returns are not accepted for special order or tuning products unless the unit is deemed faulty.

(keyword: efi)

Images are supplied by the manufacturer and may be generic. While all efforts are made to provide accurate pictures, there may be differences in the actual product, such as colour, quantity, version, or included components. Please carefully review the description and specifications for details on inclusions or any variations. Some items may be sold individually or in sets, and images may occasionally depict additional products or quantities not included in your purchase. For assistance or clarification, please contact customer support.

Specifications

Reference Information

Reference Data (Provide these details to our support team)
Brand Name/s Holley, Hilborn, Holley Efi, Retrobright, Terminator X
StreetFX SKU hly558-420
SFX Item ID 4782203
Accounting SKU hly-558-420
Manufacturer SKU 558-420
Manufacturer UPC 090127688519
Alternative References 558-420, HLY-558-420, HOL558-420

Fuel Injection System Wiring Harnesses, Holley EFI, Auxiliary Input/Output Harness, Terminator EFI, Gains 4 Inputs/1 Output, Each

Holley Terminator EFI wiring harnesses are replacement throttle body wiring harnesses and engine control wiring harnesses for specific Electronic Fuel Injection kits. These relays allow you to perform functions and features that are programmed with your Holley EFI laptop software. The software also contains instructions on how to program them. Holley wiring accessories give you the expertise needed to get the job done right.

Product Attributes
BrandHolley
Manufacturer's Part Number558-420
Part TypeFuel Injection System Wiring Harnesses
Product LineHolley Terminator EFI Wiring Harnesses
UPC090127688519
QuantitySold individually.
NotesHarness contains four extra input wires and one extra output wire that the base Terminator EFI harness does not contain.

Compatibility

Loading compatibility information...