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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4.1 ★★★★★
Based on 22 reviews
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Verified Purchase
Joe
Fort Morgan, US
★★★★★ 4
Definitely tough but not enough
Color: Black & Lake Blue, Color: Black & Lake Blue
I've been searching high and low for a durable and engaging toy for my 90lb american bulldog. She's destroyed countless toys and her number of toys just keep rising. This lasted for a few hours before she was able to chew off the rubber shell. But now shes still enjoying the hard plastic ball on the inside. Its also a perfect size of ball for her as she can fit it in her jaws comfortably without any worry of he swallowing it. Wish the outside shell was more durable though.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on April 17, 2026
C
Verified Purchase
cw
Alexandria, US
★★★★★ 5
Large ball, still makes noise and hasn’t chewed it up yet.
Color: Black & Lake Blue
He loves playing with it and it actually doesn’t get swallowed up in his very large mouth. He can still bark talk with it in his mouth which is impressive due to its larger than a softball. It nice because I don’t feel like I’m shoving my hand in his mouth to get it out which baseball size or smaller things I do. He hasn’t chewed it up like he does other squeak toys and it makes lots of noise when tossed and bouncing. It’s hard and he insists on playing with it. we broke a pot when we accidentally hit the pot with the ball. He is always bringing me toys to throw down the hall as we watch tv. I’m like no not that one get a different one. I’m afraid I’ll break something with that one due to how heavy and large it is. That one is an outside toy, he still brings me this one daily and we’ve had it for several weeks now. Plus my cousin little boy just visited and he loved playing with it too. Its made out of material that’s easy to clean for the 17month old to play with in his play pen. It’s not so heavy you can’t throw it just heavier than the others I’m willing to toss down the hall.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on May 22, 2026
T
Verified Purchase
TIINSAT
Charlottesville, US
★★★★★ 5
Great dog toy
Color: Black & Yellow
Such fun toy. Excellent product
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on May 9, 2026
A
Verified Purchase
Andrew Szeszycki
San Leandro, US
★★★★★ 2
Not a chew toy.
Color: Black & Lake Blue
The inside it a hard plastic, my dog can’t chew it. Plastic on the outside is very durable, my dog likes the noise it makes and will chase it but loses interest fast. I will not buy again.
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Reviewed in the United States on April 20, 2026
L
Verified Purchase
lisa kirby
Waukegan, US
★★★★★ 5
Durable
Color: Black & Yellow
The ball is durable and makes a sound that keeps my puppy interested in playing with it.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on May 29, 2026

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