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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
4.6 ★★★★★
Based on 20 reviews
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Product Reviews
★★★★★ 5
Clean Look, Sturdy — can’t ask for more!
Size: 6 Panel-119"W, Color: Grey, Size: 6 Panel-119"W, Color: Grey
Really like how it folds so I can create kind of a doorway with two of these. Pretty easy to assemble and has an uncluttered clean look due to the smooth fabric and nice color. Oh and it’s sturdy enough for pets.
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Reviewed in the United States on September 9, 2024
★★★★★ 5
Reliable product made with care
quality has been consistently excellent every single time. It’s reliable, tastes great, and you can tell it’s made with care.
What really stands out is how it makes me feel afterward. Even after working a 12-hour overtime shift, I don’t feel as exhausted. It genuinely helps me keep my energy up.
Highly recommend if you’re looking for something dependable and effective. I’ll definitely keep ordering.
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Reviewed in the United States on March 28, 2026
★★★★★ 5
Look nice.
These were really nice for canned oysters, way better than what we can get in the stores in our area. Perfect for milk based oyster soup! the ratio is one can of cream of mushroom, one can full of milk, one can of oysters. Add butter, salt, pepper, and bring to a boil.
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Reviewed in the United States on November 10, 2025
★★★★★ 4
Does the job
Tastes like boiled oysters, so it has that nailed down.
I use it in my shrimp ramen noodles sometimes, sometimes I use it to flavor garnish dishes.
Best price I could find, but apparently it is a specialty product.
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Reviewed in the United States on September 16, 2020
★★★★★ 5
Unparalleled source of heme iron.
This stuff is medicine if your are anemic or have low serum iron. Elemental iron from veggies or pills must be prepared by your body to carry oxygen in hemoglobin. Not so with iron from animals and oysters are unparalleled in iron content. Even if you don't find them delicious you will find them efficacious.
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Reviewed in the United States on October 13, 2025