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Ships within 48 hours · Estimated delivery Aug 13 - Aug 18
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 27 reviews
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Product Reviews
★★★★★ 5
Unbelievable toy for aggressive chewers
Color: Green Cactus
Great toy for aggressive chewers! I'm not one to hand out 5 star reviews but this one I 100% believe in. I bought the first one in 2023 and just replaced it because it broke. Now this is not a played with every once in a while, this was played with daily as it is his favorite toy. Very few toys last long but this one has went beyond my expectations. Could not be happier.
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Reviewed in the United States on May 28, 2026
★★★★★ 3
Not Recommended!
Color: Green Cactus
Be aware that with major chewers it is not durable. My dog tour right through it and was eating pieces off of it. Thankfully we got the pieces back out of his mouth but definitely not for tough chewers. Also only lasted 2 days in decent condition and was only used on the occasion throughout the day.
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Reviewed in the United States on April 22, 2026
★★★★★ 1
Not strong lasting
Color: Green Cactus
Didn’t even last 3 hours in my house. Too rubbery and our frenchie mix was able to bite pieces off and was trying to eat them. Don’t recommend as a super chewer or consider it durable
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Reviewed in the United States on May 31, 2026
★★★★★ 5
Very durable!
Color: Pink Cactus
One of the few actually tough chew toys for dogs who tear apart toys in seconds! My dog loves this thing and has yet to break into the rubber!
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Reviewed in the United States on May 6, 2026
★★★★★ 5
Great for a chewer
Color: Dogwood (Brown), Size: Large (Pack of 1)
My dog loves a hard toy and a durable one. My dog has been chewing on this for months and it is still holding strong. Because it is a hard toy when my dog brings this into another room with a hard floor and drops the toy it can be startling. My dog will choose this toy over others on a daily basis and brings the toy to other rooms.
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Reviewed in the United States on May 19, 2026