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Ships within 48 hours · Estimated delivery Sep 17 - Sep 22
For Your Every Summer RSVP, with Code: SUMMER15
Description
Holley HP EFI ECU and Harness Kits 550-604NHP ECU AND HARNESS, MPFI, NTK 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
HP ECU AND HARNESS, MPFI, NTK
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:
- 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
- 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 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
- Universal
Specs
| Brand | Holley EFI |
|---|---|
| Emission Code | 3 |
| Ignition Type | Coil - (No Timing Control) |
| Ford TFI | |
| GM HEI Small Cap | |
| Holley Dual Sync Distributor | |
| Injector Connector | Jetronic / Minitimer (Bosch) |
| Product Type | HP EFI Kit |
| Part Number | 550-604N |
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
4.8 ★★★★★
Based on 27 reviews
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Product Reviews
★★★★★ 5
Highly recommend
Color: Tie-dye Brown, Size: Throw (50" x 60")
My favorite blanket for cold nights! So soft! I’ve washed it several times and it does not shed. The quality doesn’t not disappoint. The size is perfect for curling up (not for sharing).
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on March 25, 2026
★★★★★ 5
Luxurious feel
Color: Light Brown, Size: Throw (50" X 60")
This blanket is soft and fuzzy. It has a little weight to it so it’s great to snuggle up on the couch with. Double lined makes it feeling luxurious. Haven’t noticed any shedding yet I’ve had it for a month and have washed it a couple times.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on May 7, 2026
★★★★★ 5
Absolutely Excellent
Color: Pink, Size: Throw (50" X 60")
This blanket is a Comfrt Dupe!! Ultra soft. My new favorite!!
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on May 28, 2026
★★★★★ 5
amazinggg!!
Color: Light Brown, Size: Throw (50" X 60"), Color: Light Brown, Size: Throw (50" X 60")
i loveee this blanket. after opening and breaking the air seal i threw it in the dryer for 20 minutes to fluff it up and it's perfect. it's very thick and slightly weighted (3-5 lbs) and super duper stretchy. it's double sided so you can use it facing any way you want. i've never tried either brands but from everything i've seen, this is pretty much an exact duplicate to the lola brand and comfrt brand blankets. i do wish they made more size and color options but other than that i'm obsessed. (for size comparison reference, i have a queen bed!)
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on April 26, 2026
★★★★★ 5
Incredibly soft!
Color: Cream, Size: Throw (50" X 60")
I absolutely love this Bedsure blanket! It is incredibly soft right out of the package and feels cozy without being too heavy. The fabric is plush and smooth, making it perfect for lounging on the couch, layering on the bed, or staying warm during chilly nights.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on January 4, 2026
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