SKU: 75336389254

HP EFI ECU & Harness Kits - 550-605N

Sale price$1349.97 Regular price$1499.97
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Ships within 48 hours · Estimated delivery Jul 31 - Aug 5

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Description

HP EFI ECU & Harness Kits - 550-605NOverview: 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 along with additional

Overview:

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 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 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:

Year Make Model Submodel Engine Size
Universal

Specs:

Brand Holley EFI
Emission Code 3
Ignition Type Coil - (No Timing Control)
Ignition Type Ford TFI
Ignition Type GM HEI Small Cap
Ignition Type Holley Dual Sync Distributor
Injector Connector Jetronic / Minitimer (Bosch)
Product Type EFI System
Shipping Notes
  • Free Standard Shipping on $100+ Orders to the USA.
  • Except Preorder products are shipped in 48 hours.
  • Delivery to the USA:
  1. 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
SKU: 75336389254

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4.0 ★★★★★
Based on 15 reviews
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Verified Purchase
J. Randle
Los Angeles, US
★★★★★ 5
Love them
Color: Pink & Beige, Size: Medium/Large(fits size 8 to 11)
I wear a size 11.5 in ladies shoe and these just barely fit. Butttt after I put lotion on my feet and slipped these on and left them on for about 30 mins. It left my feet really soft! They work great as intended. Would buy again
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on January 31, 2026
V
Verified Purchase
Vonda Kioultzopoulos
Fort Morgan, US
★★★★★ 3
Effective but may be uncomfortable
Color: Pink & Beige, Size: Medium/Large(fits size 8 to 11)
I have eczema on my feet and use a prescription cream that I leave on overnight. I often have a problem sleeping in socks but the silicone feels cool on my feet. The only drawback I have is the opening of the socks feel very tight around my ankles making them uncomfortable on me. I wish the opening was a bit more flexible.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on September 20, 2025
T
Verified Purchase
Tessy
Massapequa, US
★★★★★ 1
Burned my already sensitive feet, too big
Color: Pink & Beige, Size: Medium/Large(fits size 8 to 11)
Feels icky, and the heat gets trapped and literally felt like my feet were being burned by these. The bottoms of these feel prickly and they are way too big. You have to sit still and cannot walk in them.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on April 22, 2026
M
Verified Purchase
Ms. Mac
Bozeman, US
★★★★★ 5
Just as good as paraffin wax
Color: Pink & Beige, Size: Medium/Large(fits size 8 to 11)
I might prefer these socks over paraffin wax. They are comfy and very moisturizing. I use these socks once a week to keep the heels and soles of my feet moisturized between pedicures. I rinse with warm, soapy water then hang to dry. They are hard to walk in, but there's a saying printed in the socks that's says something to the effect of "take a break, stay off your feet" lol I love that as a reminder to put my feet up and relax
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on April 9, 2026
S
Verified Purchase
SKI
Chelsea, US
★★★★★ 5
Love these!
Color: Pink & Beige, Size: Small(fits up to size 7)
Love these! As I write this review, I’m sitting in my recliner with these on. I have had other silicone socks in the past and would like to share a few of the things that I have learned. These fit great! The others were 2-3 sizes too big because you could not order a size. I wear a size 7 women’s shoe. I got the smaller size. I walked around my apartment in my old ones and they got kinda yucky. Now, I sit in my recliner, put them on and chill for a few hours. I now take them off and put in a ziplock bag so they stay nice and clean (no cat hair!). I use them once a week usually on Saturday or Sunday as I’m a working girl. Also, I use Auqaphor before I put them on and put cotton socks on after I’m finished. Your feet will be SO soft. This is not a one and done…I do this every week especially during sandal season! I know this was lengthy and I hope you got some tips.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on April 25, 2026

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