SKU: 44499070246

Holley HP EFI ECU & Harness Kit (HO550-601)

Sale price$2636.55 Regular price$2929.50
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Description

Holley HP EFI ECU & Harness Kit (HO550-601)HO550 601 HP EFI ECU WITH HARNESS Suit GM TPI & Holley Stealth Ram Part Number: HO550 601 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

HO550-601 - HP EFI ECU WITH HARNESS

Suit GM TPI & Holley Stealth Ram

Part Number: HO550-601

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/Meth

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.
  • To process your return/exchange, please contact us at [email protected]
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SKU: 44499070246

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Janet C.
Draper, US
★★★★★ 3
Cute but potentially a choking problem
Color: Pink
My 5 month old miniature poodle actually bit off the little knobs on a couple of these toys. Needless to say I took them all away from her. They are cute toys but not really safe
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Reviewed in the United States on June 14, 2025
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Tyler Durden
Port Orchard, US
★★★★★ 5
Goldilocks of dog toys!
We recently rescued a small/medium bulldog breed (35lbs) and she *loves* toys. Problem was that our other dog's (75lbs) toys were too big. They literally were the size of her. We found that our new baby pooch was constantly raiding our cat's bed with the cat toys. They were more her size and she knew it. I bought her some cat toys (mostly mice with catnip inside and a yarn tail). She *loved* them, but they were too small. She would choke on them and I would literally have to pull them out of her throat by the mouse tail. Scared us too much so we gave (all 20) away to a friend. I scoured Amazon and found these whimsical toys and they are *JUST RIGHT*! Perfect size, have held up several days of chewing and gnawing, squeak pretty well, and my big dog also loves them! These deserve the 4.9 (5.0 but can't please everyone) rating that lead me to purchase them in the first place. Buy with confidence for your medium size (or any size really) fur baby!
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Reviewed in the United States on February 4, 2026
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HandR
New York, US
★★★★★ 5
Super Cute!!
These adorable toys are incredibly cute! My 9-week-old puppy absolutely loves them. There are so many different options that I can easily rotate them to keep him entertained and prevent boredom. So far, they have held up well against his teething, and I've even needed to wash a few of them in my washing machine due to potty training. They are perfect for small dogs and puppies and offer great value for the price.
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Reviewed in the United States on April 28, 2026
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All Dogs...
Dallas, US
★★★★★ 5
Great bargain and well made
Great assortment of shapes and bright colors. Just the right size for my 15lb terrier mix
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Reviewed in the United States on June 6, 2026
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Laurie A Canning
New York, US
★★★★★ 5
So cute, good quality
So cute!! I got these for my dog’s Christmas stocking and they were so cute and fun. Good quality for the price.
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Reviewed in the United States on April 16, 2026

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