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

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Exchange/Return Notes
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SKU: 33339934358

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Katie
Carnegie, US
★★★★★ 2
It's a do-not for me
Color: Ring
Bought for my doodle and the toy lasted less then two days. Not very durable. Inside the toy were layers of what looked like felt. Took it away from dog
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Reviewed in the United States on June 22, 2025
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MAW2002
Chelsea, US
★★★★★ 5
Tough toys for tough girls
Color: Ring
I have 3 large dogs that are proficient at destruction and extremely aggressive chewers. Few toys survive them. I bought several of these toys and they have been put through the ringer but still in great shape. Definitely worth it in my book. I wish there were more cute options but cute doesnt typically last for these 3.
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Reviewed in the United States on November 18, 2025
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Kate Yamokoski
Louisville, US
★★★★★ 5
Great chew toy for my golden retriever .
Color: Ring
My golden retriever loves this toy . And she has not chewed it up . I bought several of them . It is durable and she is an aggressive chewer with toys .
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Reviewed in the United States on May 29, 2025
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The Big Guy of Michigan
Grantham, US
★★★★★ 5
Dog chew toy
Color: Ring
Well made, too big & heavy for small-medium dogs.
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Reviewed in the United States on February 2, 2026
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ZC
San Leandro, US
★★★★★ 4
My dogs go CRAZY for these!
Color: Ring
My Pitbull and Frenchie go CRAZY for these! They do have a leathery type smell to them if you’re sensitive to that (doesn’t bother me) and my dogs WILL ingest what they tear off if I don’t watch them closely. Only removing 1 star because of how fast my dogs tear these apart and how deliciously enticing they apparently are to ingest, but my dogs may just be psychopaths. :)
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Reviewed in the United States on September 13, 2025

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