Holley HP EFI ECU Kit With Wiring Harness For Ford Modular 2-Valve Engine 1999-2004



  • 4 Programmable Inputs/Outputs
  • Supports Range of Controls
  • Plug and Play Installation
  • Made in the USA
MSRP $2,835.00
You save 10%

Holley HP EFI ECU Kit with a Wiring Harness for 1999, 2000, 2001, 2002, 2003 and 2004 Mustangs with a Ford Modular 2-Valve Engine.

If you’re on the hunt for the perfect new EFI ECU kit for your 1999-2004 Mustang and you need one for a Ford modular 2-valve engine, then be sure to pick up this Holley (550-616) HP EFI ECU Kit with a Wiring Harness that’s now available at CJ Pony Parts! 

Features & Benefits:
- Equipped with 4 Programmable Inputs and 4 Programmable Outputs Ideal for 2-Valve Engines with Single Power Adder
- Allows User to Configure System to Support Wide Range of Controls Including Boost Control, Progressive Nitrous, Water/Meth Injection, Speed Inputs, Fuel Pump Control, AC Inputs, Timing Retard Inputs and Various Other Uses
- Designed to Specifically for 1999-2004 Ford Modular 2-Valve Engines
- Plug and Play Installation for Use with Factory Sensors (Crank, Cam, TPS, Coolant Temp and More)
- Plug and Play with Factory Actuators (Coil, Injectors and IAC)
- Connectors for Holley Fuel Pressure and Oil Pressure Sensors
- Connectors for Expanded Inputs and Outputs
- ECU Certified to ISO 8846, SAE J1171 and United States Coast Guard Requirements for Ignition Protection and Fire Resistance 

This Holley (550-616) HP EFI ECU Kit with a Wiring Harness comes equipped with 4 programmable inputs and 4 programmable outputs that are ideal for 2-valve engines with a single power adder. This allows you to configure the system to support a wide range of controls, like boost control, speed inputs and more! It’s a plug-and-play installation and comes with connectors for Holley fuel pressure and oil pressure sensors. 

This Kit Includes:
- Holley EFI ECU
- Bosch Wideband Oxygen Sensor
- Map Sensor
- Coil Drivers
- All Necessary Harnesses

California Residents: Proposition 65 Warning

Only for use on pre-pollution controlled vehicles: This product can be used on vehicles that were manufactured before emissions control regulations were imposed. Pre-pollution vehicles are defined as:

  • 1965 and older U.S. manufactured California certified vehicles
  • 1967 and older U.S. manufactured federally certified vehicles

Installation Difficulty


Advanced skill is required for this installation.

Vehicle Fitment

This product will fit the following Mustang years:

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