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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4.8 ★★★★★
Based on 30 reviews
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beck
Waukegan, US
★★★★★ 5
Dogs Favorite Ball
Size: Large (Pack of 1), Color: Multi
Great fetch ball! Super durable rubber that holds up way better than a regular tennis ball and has an awesome bounce. Easy for dogs to spot and perfect for endless games of fetch. Doesn’t get soggy or fall apart — definitely a must-have for active dogs!
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on April 29, 2026
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tin
Alexandria, US
★★★★★ 5
Bounces good
Size: Large (Pack of 1), Color: Multi, Size: Large (Pack of 1), Color: Multi
My dog loves this ball ,,the ball is a thick rubber ,and is flexible that even my little dog can carry it in his mouth, it does bounce really good , I recommend this ball if your dog likes chasing after balls. If you have a fenced in yard I do not recommend bouncing it hard because it might go over the fence. UPDATE I have had this ball a few days now and my dog likes to chew on his toys and tear them apart, one time he had a tennis ball and he managed to tear it apart but this ball he has yet to tear apart,
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on May 5, 2026
R
Verified Purchase
Ronda S
Los Angeles, US
★★★★★ 5
Chuck It Balls!! Best Loved Fetch ball by my Dog!!
Size: Large (Pack of 1), Color: Multi, Size: Large (Pack of 1), Color: Multi
Chuck It large Whistle balls, Absolutely love these great rubber balls, I think there is at least 20-25 balls all over my house, yard and in my boys toy box. At least one is trapped until fall on our ravine hill side, they do bounce high and off his snout for more travel time.!! (Over the fence and into ravine) I subscribe and save getting usually 1 or 2 a month, Really… makes it easy to find one, when they are everywhere!!😜 They are usually blue in color, once in awhile I get an orange one (which I prefer, easier to find in the grass/bushes) These do have a light whistle sound when throwing and my dog will change direction hearing where they are headed. These balls are very durable and last a very very long time. Actually I don’t think one has worn out.. lost yes…. Definitely get the large size, perfect for a med to large dog to play fetch forever!!
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on August 15, 2025
C
Verified Purchase
coach
Grantham, US
★★★★★ 5
Love this ball!
Size: Large (Pack of 1), Color: Multi
My doberman and her dog friends love this large high bounce rubber fetch ball! She loves to chew it endlessly between throws and her Rottweiler buddy loves to do the same because it has a hole through it. I definitely recommend the large 3 inch ball for larger dogs.
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Reviewed in the United States on November 15, 2025
M
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Michael Murrell
Belleville, US
★★★★★ 4
The orange ones are perfect!
Size: Medium (Pack of 2), Color: Assorted
I wish I could give 4 1/2 stars but it isn't possible. The reason why I don't give 5 stars is because no one sells these in a 2 pack of just orange balls. I was able to find blue only but not orange only. I have a pitbull and so does my good friend. We take our dogs out all the time and they absolutely love chasing these balls.... The orange ones to be exact. They will not play with or bring the blue balls back. They are a waste. I had to buy 2 packs to keep the oranges. I'm taking the blue ones to the local dog park and just dropping them off. Now to the reason these balls deserve 5 stars: They are super easy to throw and they also make a slight whistling noise when you throw them because of the holes. They are real easy to wash due to the material. Also, they are pretty indestructible. The only reason I'm ordering more is due to them being lost. Our dogs have never torn them apart. I'm sure they could if we let them, but we use these for chase, not as chew toys. My friend also tied a rope through one of the balls to throw and retrieve with the rope. He uses this as a fun indoor toy. These do not float in water but I buy other chuckit balls for that purpose. They have the orange balls with the blue stripe which work great in pools. The balls are awesome and I keep coming back for more. Hopefully your dogs like the blue balls.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on December 8, 2015

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