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
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SKU: 33339934358

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Battle Creek, US
★★★★★ 5
Application
Color: Medium Sunlight
Good application. Only thing is I bought the wrong color for my skin
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Reviewed in the United States on February 11, 2026
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Terra Todd
Natrona Heights, US
★★★★★ 5
Not for older skib
Color: Medium Sunlight
This is very nice but settles into fine lines
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Reviewed in the United States on October 16, 2025
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Ayesha Yasmin
Whiting, US
★★★★★ 5
A protective formula that protects and radiates skin all day
Color: Light Beige
I like the pressed foundation for smooth and bright look on face.
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Reviewed in the United States on January 23, 2025
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Jessica Littleton
Fort Morgan, US
★★★★★ 5
Azelaic Acid Sunscreen A MUST!!!! BEST sunscreen!!!
Style: Acne/Rosacea Prone Skin
Finally!!!!! I have found a sunscreen that actually helps my skin!! I have tried so so so many! Around 25 different types! From $-$$$$! This one is so great! It is still a sunscreen and feels a bit of a sunscreen at first but once it has set it is amazing! I would absolutely recommend! I have acne prone, dry, sensitive skin and this has not broken me out isn't heavy and hasn't inflamed my skin. It has actually improved my skin. I like the lower list of ingredients as well. I use Retin-a 0.1% (at night) and use a moisturizer AM&PM (person and covey DMl) under this. I would say it isn't a stand alone moisturizer. Would recommend this! And will be buying another one once this one is out! Pros: Liquid/watery consistency Minimal ingredient list Works great with makeup Layers nicely No white cast Easy to remove Nice packaging Good price point Great for acne/acne prone skin Flaky skin approved Not shiny Actually helped my skin Azelaic acid Cons: Slightly like applying sunscreen at first
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Reviewed in the United States on November 9, 2025
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Jasmine
Massapequa, US
★★★★★ 5
Great product
Style: Acne/Rosacea Prone Skin
Really love this sunscreen. I was using shiseido before which has a nice texture but this one I honestly think is better. It doesn’t burn my eyes when I’m at the gym like other sunscreen too. Don’t usually need to wear a moisturizer with it because it is moisturizing, but I guess some people may consider a con depending on what you’re looking for. I am a super oily girl in general and I would say if you are sensitive to that then maybe try one of their more mattifying ones which I plan to do after I run out of this one. Otherwise, I don’t think I will change brands for SPF after trying this.
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Reviewed in the United States on April 17, 2026

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