SKU: 33339934358

Holley HP EFI ECU & Harness Kit (HO550-605)

Sale price$2633.85 Regular price$2926.50
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Description

Holley HP EFI ECU & Harness Kit (HO550-605)HO550 605 HP EFI ECU WITH UNTERMINATED Unterminated Universal Harness Part Number: HO550 605 Looking for a plug and play alternative for your stock or built late model factory EFI engine? How about a replacement ECU for your older Holley C950? Holley has you covered. HP EFI ECU and harness kits are designed to be used with popular factory EFI engines as an alternative to the factory ECU and harness or as a replacement for your C950 ECU. The HP allows

HO550-605 - HP EFI ECU WITH UNTERMINATED

Unterminated Universal Harness

Part Number: HO550-605

Looking for a plug and play alternative for your stock or built late model factory EFI engine? How about a replacement ECU for your older Holley C950? Holley has you covered. HP EFI ECU and harness kits are designed to be used with popular factory EFI engines as an alternative to the factory ECU and harness or as a replacement for your C950 ECU. The HP allows you to accurately control the fuel and ignition of your engine along with additional controls for nitrous, boost or water meth.
NEW V2 SOFTWARE FEATURES:
"Quick Start" ignition and fueling strategy for LS x Engines
Data Logger. Scalable axes, Smoothing, Multiple graph view ability, Pre-defined notes fields and many more
Strip Chart Real-Time Data Viewer
Integrated Boost Control - Boost vs Time, Boost vs Gear (Time or RPM), Boost vs RPM, Boost vs Speed, Launch control. Boost launch builder, Over-boost safeties, Boost scramble
Traction Control - Power reduction via timing, nitrous percentage or boost (Requires Davis Technologies Holley Module)
"Quick Start" fueling for all engines
Option for VE based fueling strategy
Fuel Map and Learn Function Smoothing
Configurable User Password Protection
Fully Configurable lap top Gauge Panel
FEATURES:
Optional 5.7” full-color touchscreen LCD allows easy on-the-fly tuning,data-logging or can be used as an easy to see graphical gauge panel
Eight sequentially driven 8:2 peak and hold injector drivers, capable of driving up to 16 low or high impedance injectors as a standard feature. Multiple staged injector strategies
Eight channel Distributorless Ignition (DIS)outputs capable of directly driving “Smart” ignition coils or Holley DIS coils. Will drive 2 wire coils with the addition of PN 554-112 high current coil driver module
Plug and Play control of factory GM 24x and 58x LSx engines
Integrated single channel wide band oxygen sensor control. Works with NTK or Bosch sensors
Internal data-logging 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 allows you to unlock your engine’s potential
Works with 4, 6, 8 cylinder engines
Unique lb/hr based fueling strategy greatly simplifies and commonizes tuning
Advanced idle, closed loop, and enrichment strategies allow for very stable operation
ECU is 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. New Plug and Play applications in process. Custom settings can be configured to allow many other applications
1-5 Bar MAP sensor capability
Two channel knock control sensor Inputs for both one or two wire knock sensors
Dedicated fuel and oil pressure inputs
Controls both stepper and PWM Idle Air Control (IAC) motors
Speed density, Alpha-N, or combination fueling strategies
4 Programmable high or low Pulse Width Modulated (PWM) outputs and 4 fully configurable inputs can be configured for use
4 Stage nitrous oxide control
Fully featured nitrous control eliminates the need for a separate nitrous controller device
Can be configured “Wet” or “Dry” with closed loop feedback
Progressive control based on time, RPM, or boost, requires part # 554-111
Lean or rich safety cutoff
Full timing retard/control configurability per stage based on RPM or time
Integrated Water

Shipping Notes
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Exchange/Return Notes
  • We offer a 30-day return/exchange service after receiving.
  • Final sale items are not eligible for returns or exchanges.
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SKU: 33339934358

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Stephanie Taylor
Battle Creek, US
★★★★★ 1
Stand
Size: 16 Inch
Didn’t work for what I wanted them for
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Reviewed in the United States on April 16, 2026
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dwheel
Port Orchard, US
★★★★★ 3
There is no side to side stability
Size: 28 Inch
This product was easy to assemble and install and came with all parts. The product itself is very sturdy, looks good with a nice industrial aesthetic BUT - there is ZERO stability side to side (lengthwise) as the plates which attach to the wood are too small. I have them set closer than the picture so it is not an issue of being too far apart. If anyone else had this problem AND FIGURED OUT A FIX FOR IT - please share!!
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Reviewed in the United States on June 5, 2023
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Kindle Customer
Waukegan, US
★★★★★ 5
Love those legs
Size: 28 Inch
People love the look of these legs .. they are arty and cool
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Reviewed in the United States on May 27, 2025
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Doogie Howser
Carnegie, US
★★★★★ 5
Fairly stable. Good value for the price
Size: 16 Inch, Size: 16 Inch
Great set of stands. You have to tighten them pretty snugly to minimize wobble. Given they are metal they’ll have a little bit more give than solid wood. Even so, a tall desk I built with them remains stable and level.
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Reviewed in the United States on December 22, 2025
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Amazon Customer
Boise, US
★★★★★ 5
Quality
Quality item. Using a butcher block on top to make a desk.
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Reviewed in the United States on May 13, 2026

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