558-420 Terminator EFI In/Out Kit

Name: 558-420 Terminator EFI In/Out Kit
Brand: HOLLEY
SKU: 510-558-420
Price: 56.25 USD
Availability: InStock

^$56²⁵

1 left in stock

Ships on Sep 08, 2026

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Terminator EFI In/Out Kit

4 Extra Input Wires
1 Extra Output Wire

contains Input wires for Inputs 1-4. It contains one wire for Output 2. These inputs and outputs can perform features and functions that must be programmed via Holley EFI laptop software. The software also contains instructions on how to program these.
Emissions Note:
This part is only legal for sale and use on Uncontrolled (Non-Emissions Controlled) Vehicles or on vehicles used solely for the purposes of closed competition racing.
CLICK THIS LINK FOR IMPORTANT CARB & EPA EMISSIONS INFORMATION ABOUT THIS PART

There's a new self-tuning EFI on the streets and IT'S IN CONTROL!

The Holley Terminator EFI Systems have features not found in any other street EFI system including throttle body technology that is currently used in every NASCAR Sprint Cup Serie car. Installation is easy with no computer experience necessary, simply bolt it on, use the included handheld tuner to answer a few multiple choice questions and let the Terminator EFI take control, the system self-tunes as you drive. If you embrace modern technology and want to take control, the system is upgradable to complete laptop control without the need to purchase another electronic control unit. This carburetor replacement EFI system from the fuel system experts is perfect for street machines, off-road vehicles, trucks, RVs and weekend racers!

Terminator EFI Features:

Fully self-tuning ECU - No laptop required.
Self-tunes instantly to deliver the perfect air/fuel mixture in real time for optimized fuel economy and power.
Virtually maintenance free - keeps your vehicle reliable and ready to drive.
950 CFM Throttle Body with CFD computer designed air-entry area taken from Holley's famous NASCAR throttle body - as found on all NASCAR Sprint Cup Series cars.
Patent pending annular discharge fuel ring for maximum flow and optimum fuel atomization - No restrictions or delay in fuel flow like booster designs.
Serviceable sensors integrated into throttle body and pre-wired for a simple one-click connection.
Connections for Ford, GM TH350 and 700R4, and other transmission linkages.
Fits any square (Holley 4150) flanged intake.
80 lb/hr injectors support 250-600 HP engines.
Provides ignition timing control on engines with Small Cap HEI and Ford TFI distributors (requires adapter).
ECU fully potted and sealed for protection from vibration, dust and moisture.
Terminator ECU can be EASILY updated to Holley "HP" ECU specs with a free online software download. ECU can then be used for LSX, boosted, nitrous,and many other applications in the future as you desire!
Trouble-free performance with today's fuels - put an end to vapor lock and fuel varnish problems!