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Description
HP EFI ECU & Harness Kits - 550-601Overview: 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:
- 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
4.6 ★★★★★
Based on 16 reviews
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Product Reviews
★★★★★ 5
We LOVE these!!
Hands down the BEST dog toy we've found!! I have two pitbulls that are aggressive chewers and players.. we've had these about a month and they play with them everyday. Ordered two..still have two! They don't even have teeth marks in them. The durability is like nothing I've seen before. We've done name brand boxes specifically for bully breeds that are rather expensive, bought name brand toys that are also expensive..all broken or destroyed in a matter of a day, if that. For the price these are totally worth it! We'll be buying more down the road! I think these might actually last all summer!
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Reviewed in the United States on May 2, 2026
★★★★★ 5
This is a great ball for high energy dogs.
Color: Blue
I have a Belgian Malinois, so you can imagine the Maligator jaws. Just opened this today and let her play with it indoors. She LOVES IT. It wore her out and it’s a toy she can really stay focused on without needing me to throw or roll for her. It moves on its own! I supervised her play. I was hoping it was too big to get under the couch, but no. It goes right under it. I had to block off the gap so I didn’t have to keep getting it out from under for her. The outter “shell” is very durable! When she had resting moments, she chewed it pretty good - I could hear the material squeaking against her teeth. I was worried she was tearing it up, but nope! Not a mark on it. It’s easy to set up and operate. It needed charging before play. After hours of play, she was able to somehow unscrew the outter shell. This concerned me bc the smaller, inner ball mechanism came out but I saw it right away and was able to put it back together. So, make sure it’s screwed together tightly (which I thought I had done without breaking it) and check it from time to time to make sure it hasn’t loosened. This is a great ball for her incredible high energy drive. It gives her the work and fun play she needs to get tired, which I love. This toy is on the expensive end, but so far it’s worth it. Now we’ll see how long it lasts!
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Reviewed in the United States on October 7, 2025
★★★★★ 5
Love love it
Color: Blue
Best dog toy ever. I have a 1 year old boxer who is full of energy (understatement). This ball has provided more entertainment for us both than any dog toy I’ve ever purchased. Charge holds well and has a very resilient shell. I love it. Worth the price.
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Reviewed in the United States on May 23, 2026
★★★★★ 4
Great ball for limited entertainment. Replaceable outer shell is an amazing option!
Color: Blue, Color: Blue
Bought this for our 45lb, ball-obsessed Dutch shepherd/pit bull dog mix. I had one of these years ago with the hard shell and couldn’t be happier with the new foam shell.
The new foam shell is much quieter and while our dog might put holes in it with his teeth, he doesn’t seem to ever pull pieces off.
For engagement level, he found it VERY interesting at first and was scared to grab it, but once he got over that he started holding it in his mouth even when it shakes and just tries to keep it.
Isn’t the best for fetch or anything as he has trouble letting it go when it is actively moving, but it makes him happy while he has it. We just make sure to monitor him while it is out.
The ability to change the outer shell and just buy a replacement for the shell instead of a whole new toy is a lovely feature that makes me very happy to continue buying from this company.
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Reviewed in the United States on April 19, 2026
★★★★★ 5
Great Interactive Option
Color: Blue
To start, I have been very happy with this purchase. A couple of key points for me are durability and being able to keep my dog's attention. I have had it for almost a year, just a month shy, and she hasn't managed to get through the foam outer shell even though she tries real hard to do so. Let's just say, she's hard to find toys for because of her habit of finding the point of failure where she can pick and gnaw at until the toy is no longer safe for her to have. With this toy, she not only found her match, but it also has her watching, waiting, and even stalking. Only one small issue has recently occurred: the motor has started having an issue where the charge doesn't hold, and it doesn't remain on afterwards. I have reached out to Cheerble directly to see about replacing it since I am still within their 12-month timeframe, and they responded right away.
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Reviewed in the United States on April 22, 2026