SKU: 34360476229

HP EFI ECU & Harness Kits - 550-601N

Sale price$1349.97 Regular price$1499.97
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Ships within 48 hours · Estimated delivery Jul 11 - Jul 16

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Description

HP EFI ECU & Harness Kits - 550-601NOverview: 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

Overview:

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.

Features:

  • 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/Methanol injection control
  • Uses Holley Water/Meth solenoids specially designed and calibrated for use with this EFI system to allow the user to enter Water/Meth flow as a percentage of fuel injector flow for Water/Meth tuning precision unmatched in the industry

Application:

Year Make Model Submodel Engine Size
Universal

Specs:

Brand Holley EFI
Emission Code 3
Ignition Type Coil - (No Timing Control)
Ignition Type GM HEI Small Cap
Ignition Type Holley Dual Sync Distributor
Injector Connector Jetronic / Minitimer (Bosch)
Product Type HP EFI Kit
Shipping Notes
  • Free Standard Shipping on $100+ Orders to the USA.
  • Except Preorder products are shipped in 48 hours.
  • Delivery to the USA:
  1. Standard Shipping : 3-10 business days
  • If time is of the essence, please consider selecting expedited delivery for faster service.
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]
  • Please click here for more details>>> Return & Exchange Policy
SKU: 34360476229

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AngelKlein2275
Carnegie, US
★★★★★ 3
WEIRD feature - requires a water bottle
Color: Cow, Size: Large
Cute, but buyer beware. Maybe the description said this, but who would think to read for this.... You have to insert an empty bottle (like an old water bottle) for it to make the crinkle noise. There is a velcro spot at the base where you can open it and insert the water bottle for the noise factor and your dogs entertainment. I've yet to do that, but feel like my dog is gonna figure out the velcro and get the bottle out in no time. Seems like a waste of money. I could just give her an empty water bottle without the toy for free.
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Reviewed in the United States on June 9, 2026
A
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Alice
Dallas, US
★★★★★ 5
Best dog toy!
Color: Multicolor/Alligator & Wild Duck, Size: Medium, Color: Multicolor/Alligator & Wild Duck, Size: Medium
Best dog toy! Most dog toys lady maybe a week or less but this one has been going strong for almost 2 months. Both the squeekers still work on both toys i purchased. My vizsla loves ti squeek and carry it around. We added an empty water bottle in the pocket cavity for some extra fun! Yes, we are still on the same water bottle! Fantastic durability.
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Reviewed in the United States on May 26, 2026
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Amy Jo
New York, US
★★★★★ 3
Shows wear quickly
Color: Multicolor/Sheep & Cow, Size: Medium
These are cute but not holding up as well as I had hoped. Quality is ok and the Velcro has held up great. The fabric just isn’t as good as it could be. They are much larger than expected.
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Reviewed in the United States on April 28, 2026
R
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Rachel
Pawtucket, US
★★★★★ 5
Super Sturdy with hours of fun.
Color: Wild Duck, Hare, Squirrel & Alligator, Size: Small
I got the small ones that you cannot put a water bottle in. These toys have held up way better than expected. I am dog sitting a very rough with toys dog named Chunk. He tears up ever. Single. Toy my dog (Ted) has. I bought new ones just for chunk. These appealed to me with the no stuffing, They were cheaper, and have a squeaker. Everything chunk needed. They arrived on time and I thought I wasted my money. They were super soft, like too soft. They felt flimsy and weak. Like 5 minutes with chunk and they be dead. 2 hours with my dog and they would have a rip. So far 2 of them (I set two out) have lasted the whole weekend. The bunny looks very rough and disgusting, but no rips, the squeakers still work, and no random fluff everywhere. I am going to wash the bunny once chunk leaves. My very careful doggo Ted loves them too. He throws them up in the air and catches them, plays tug of war with them, and no rips. They are super sturdy. He can’t wait until Chunk leaves (chunk is 2 and Ted is 12-13) so he can play with them.
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Reviewed in the United States on April 26, 2026
A
Verified Purchase
Amber B.
Phoenix, US
★★★★★ 5
Loved it
Color: Brown/Wild Duck, Size: Large, Color: Brown/Wild Duck, Size: Large
He loved it so much, he destroyed it so we ordered another. I didn't realize that you can stick an empty water bottle inside. Again, the first one didn't last long, but he enjoyed it
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Reviewed in the United States on May 20, 2026

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