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For Your Every Summer RSVP, with Code: SUMMER15
Description
Holley HP EFI ECU and Harness Kits 550-606NHP ECU AND HARNESS, FORD MPFI, NTK Looking for a alternative for your stock or built late model factory FORD 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
HP ECU AND HARNESS, FORD MPFI, NTKLooking for a alternative for your stock or built late model factory FORD 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:
- 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
- Includes NTK wideband oxygen sensor
Application
- Universal
Specs
| Brand | Holley EFI |
|---|---|
| Emission Code | 3 |
| Ignition Type | Coil - (No Timing Control) |
| Ford TFI | |
| Holley Dual Sync Distributor | |
| Injector Connector | Jetronic / Minitimer (Bosch) |
| Product Type | HP EFI Kit |
| Part Number | 550-606N |
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
4.2 ★★★★★
Based on 15 reviews
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Product Reviews
★★★★★ 5
Easy to install
Size: 24x7.9, Color: Black
Easy to install and look great as floating shelves.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on April 4, 2026
★★★★★ 3
Good Stability, But Quality Could Improve
I bought this bathroom shelf on Amazon and overall, I’m fairly satisfied with the purchase. It is sturdy and holds my items securely without wobbling. The assembly process was straightforward and didn’t take much time. However, I did expect it to be a bit wider based on the pictures, so make sure to double-check the measurements before ordering. I also wish the overall quality of the materials was a little better, as some parts feel slightly less durable than I expected. That said, it still does the job well and serves its purpose. It’s not a bad purchase, especially if you’re looking for something functional and affordable.
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Reviewed in the United States on February 24, 2026
★★★★★ 5
Sturdy and good looking.
Size: 24x5.8, Color: Black, Size: 24x5.8, Color: Black
Great shelves. As you’d expect - and mounting is just fine if you pay attention and hit some studs. I’ve got my wife’s plants on these for over a year with no problems.
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Reviewed in the United States on October 26, 2025
★★★★★ 5
Great shelves
Size: 16.5 Inch, Color: Rustic Brown
I loved these for my room, they were easy to install and super versatile, I love how easy it was to assemble them and how functional they became once I was done setting them up. They fit perfectly next to each other and I love how my room looks nice since I don't like relying on bookshelves or anything of that category and rather have wall shelves. They are really stable and I love how they look, they are also really easy to clean since I spilled some baby powder from my last waxing session and they clean up pretty well. Overall, just know that these shelves are super stable, durable and versatile, I love how many things can fit on it if you know how to organize or don't have much stuff to put on them; it's all up to you and what you need them for, so I recommend them 10/10!
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Reviewed in the United States on December 22, 2025
★★★★★ 5
Great shelves! Had for years!
Size: 16.5 Inch, Color: Rustic Brown, Size: 16.5 Inch, Color: Rustic Brown
I love these shelves, I’ve had them set up both ways, as a floating shelf and the other way where you get some side support. I’ve had them for years, moved with them, and they continue to work great. I’ve had a lot on them too weight wise (I love books) and they don’t cave in the middle. Great shelves and easy to assemble (I’m a newbie with a drill). Great value for the money, durability is great, adjustable, and great for what you get!
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Reviewed in the United States on May 2, 2026