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Home Ignitions & Electrical Holley HP EFI ECU and Harness Kits 550-604
Mopar Replacement Engine Control Modules 68363277AA
Mopar Replacement Engine Control Modules 68363277AA $2,246.00
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Holley Terminator X MAX Engine Management Systems 550-1411
Holley Terminator X MAX Engine Management Systems 550-1411 $2,351.00

Holley HP EFI ECU and Harness Kits 550-604

$2,347.00

Engine Management Systems, HP EFI, ECU and Harness, Up to 16-Injectors, 8-Coils, Four Digital Inputs, Wideband, CANBUS, Universal, MPFI, Kit

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Category: Ignitions & Electrical
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Description

Overview

Brand: Holley
Manufacturer’s Part Number: 550-604
Part Type: Engine Management Systems
Product Line: Holley HP EFI ECU and Harness Kits
Summit Racing Part Number: HLY-550-604
UPC: 090127666944
Transmission Controller Included: No
High Impedence Injectors: Up to 16
Low Impedence Injectors: Up to 16
Coils: Up to 8
Digital Inputs: 4
Wideband Controller: Yes
Wideband Channels: 1
CANBUS Enabled: Yes
CANBUS Networks: 1
Knock Control: Yes
Knock Channels: 2
Drive-By-Wire Capable: No
VVT Control: No
Boost Control: Yes
Nitrous Control: Yes
Traction Control: Yes
Launch Control: No
Engine Protection: Yes
Flex Fuel Compatible: No
Multi-fuel Capable: No
Data Logger: Yes
Oxygen Sensor Included: Yes
Display Included: No
Handheld Controller Included: No
Remanufactured: No
Quantity: Sold individually.
Notes: Universal V8 MPFI fit. Requires ignition adapter harness based on ignition type.

Holley HP EFI ECU and Harness Kits

Holley HP EFI ECU and harness kits allow you to manage automotive functions—like the fuel and ignition of your engine, along with controlling nitrous, boost, or water/methanol. Select the model with options needed for your vehicle application. (Note: some models are engine-specific.)

Features and notes:

* Eight sequentially driven 8:2 peak and hold injector drivers capable of driving up to 16 low or high-impedance injectors are standard
* 8-channel distributorless ignition (DIS) outputs capable of directly driving “smart” ignition coils or Holley DIS coils
* Integrated, single-channel wideband oxygen sensor control. Works with NTK or Bosch sensors. More channels can be added via CAN bus.
* Internal data-logging is standard, with a huge 2GB of memory
* 4-stage progressive nitrous control
* Turbo boost control
* Integrated water/methanol injection control
* Self-tuning fuel table strategy greatly simplifies tuning process
* Individual cylinder fuel and spark control allow you to unlock your engine’s potential
* Compatible with 4, 6, and 8-cylinder engines
* Unique lbs./hr.-based fueling strategy greatly simplifies tuning
* Advanced idle, closed loop, and enrichment strategies allow for very stable operation
* Fully potted and can be mounted in the engine compartment or interior
* Sealed automotive and marine-grade connectors
* Allows for use of common OEM sensors, as well as customer sensor calibration input
* Ignition plug-and-play with GM 24x and 58x LSx engines, GM HEI, Ford TFI, magnetic, and hall effect trigger, and other ignition systems
* 1-5 bar MAP sensor capability
* 2-channel knock control sensor inputs for both one and 2-wire knock sensors
* Dedicated fuel and oil pressure inputs
* Control both stepper and PWM idle air control (IAC) motors
* Speed density, Alpha-N, or combination fueling strategies
* Four programmable high or low pulse width modulated (PWM) outputs and four fully configurable inputs can be configured for use
* Lean or rich safety cutoff

Shipping & Delivery
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Effective Date: August 9, 2025

At X Factors Motorsports, we are committed to delivering your order quickly, securely, and affordably.


1. Processing Time

  • Orders are typically processed within 1–2 business days after payment is confirmed.

  • Orders placed on weekends or holidays will be processed on the next business day.


2. Delivery Times

  • Domestic Shipping (United States): Delivery takes 5–7 business days from the date of shipment.

  • International Shipping: Delivery times vary by destination and may take 7–21 business days depending on customs processing and local delivery services.


3. Shipping Rates

  • United States: Free standard shipping on all orders.

  • International: Shipping costs are calculated at checkout based on the delivery address, package weight, and destination country.


4. Carriers Used

We ship orders using trusted carriers such as UPS, FedEx, USPS, and DHL to ensure reliable delivery. Tracking numbers are provided for all shipments.

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    At X Factors Motorsports, we specialize in high-performance engines, outboards, and premium automotive equipment. With expert support, fast shipping, and trusted brands, we help builders, racers, and enthusiasts power their passion — one project at a time.

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    • Phone: +1 (714) 694-3374
    • E-mail: sales@xfactorsmotorsports.com
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