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Ships within 48 hours · Estimated delivery Jul 13 - Jul 18
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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
4.5 ★★★★★
Based on 811 reviews
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Product Reviews
★★★★★ 5
Great cordless frother
Color: Black
This milk frother has been a great addition to my daily coffee routine. It comes with multiple useful accessories, which make it versatile for different drinks and easy to clean afterward. The motor is impressively powerful, producing rich, creamy foam in seconds. Exactly what you’d expect from a quality electric frother, which typically delivers fast, consistent results with minimal effort.
I also really appreciate the convenient charging base, which keeps everything organized and ready to go without dealing with loose cords. What stood out most, though, was the customer service. I had a minor issue with the buttons, and they quickly sent a replacement with no hassle. Overall, a reliable, well-designed product backed by excellent support.
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Reviewed in the United States on April 30, 2026
★★★★★ 5
Best frother for many reasons
Color: Black
I spent a long time searching for the right frother because of how much I would be using it. I make coffees, teas and protein shakes daily. I needed something more high powered than normal. Ive had others that just dont get the job done and/or dont last. (the 3 others I tried were all free gifts with a purchase of coffees or teas online. So now that i was paying for one, i wanted something better with all the good features)
Its has 3 attachments for every possible use (if u dont know what the hook one is for, its great for protein drinks or any heavier powders u need to mix) but honestly all 3 attachments work for heavier powders due to the stronger motor. U can use it for cooking as well. The stand charger is super convenient and space saving. Multiple power/level settings. Definitely a quality item but with a bargain price. The cherry on top is the customer service. They're great! responsive and very helpful. Im definitely happy with this purchase and will now be looking into see what other products they have to offer. 🙂
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Reviewed in the United States on March 29, 2026
★★★★★ 5
Excellent customer service and good product.
Color: Black
Really like this frother a lot, with the attachments. Great price and works well. That being said, it suddenly stopped working after a few months, to my dismay. However, upon reaching out to the company, they replaced it very quickly. So I do recommend it!
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Reviewed in the United States on April 25, 2026
★★★★★ 4
Great frother, dumb charger
Color: Black
Works well. I got this to replace my battery powered milk frother from IKEA. I use it to make a protein shake every day. I just take a 16oz glass, fill it halfway with milk, add a scoop of protein powder, and mix it with the frother, using a combo of low and medium power, but realistically, low is all you need for that purpose. Been using it everyday for the past almost month since I got it, haven't had to recharge it and it's still working great.
The only reason I'm giving 4 stars instead of 5 is because the charger is micro USB. Not using USB-C in 2025 is honestly just insulting. Change that and you have a 5-star product.
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Reviewed in the United States on August 12, 2025
★★★★★ 5
Best frother I have bought
Color: Black, Color: Black
Easy to use
Rechargeable
3 speeds for different nixing
Has a rechargeable stand that helps make it stand up straight
And didn’t forget to register the unit for the warranties
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Reviewed in the United States on April 28, 2026