SKU: 25982102966

Holley HP EFI ECU and Harness Kits 550-606N

Sale price$1349.97 Regular price$1499.97
Save 10%

Pay in installments of $374.99 with ShopPay, AfterPay and Klarna

Shipping Estimate
USA
  • USA
  • CAN

Ships within 48 hours · Estimated delivery Oct 11 - Oct 16

Promo Codes Available:

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, 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 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:
  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: 25982102966

Discover Niche Categories That Outsell

Top-Converting Item to Boost Your Average Order

4.1 ★★★★★
Based on 19 reviews
Sort
Highest Rating
Newest First
Oldest First
Product Reviews
B
Verified Purchase
Boreal
Chelsea, US
★★★★★ 5
Good fit. Good quality.
Size: 40W x 28L, Color: Vintage Stonewash
Good fit. Good quality.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on June 8, 2026
M
Verified Purchase
manuel holdren
Lake Worth, US
★★★★★ 5
Wrangler Authentics Men's Classic 5-Pocket Relaxed Fit Cotton Jean
Size: 50W x 30L, Color: Stonewash
I’ve been wearing Wrangler Authentics Classic 5-Pocket Jeans for a while now, and they’ve become one of my go-to pairs. The denim is 100% cotton, so it feels sturdy yet comfortable enough for all-day wear. The relaxed fit through the seat and thighs gives plenty of room to move without looking baggy, and they sit naturally at the waist, which makes them easy to wear with just about any shirt. The five-pocket design is classic and practical, and the stitching feels strong and durable. I also appreciate the heavy-duty zipper and button closure—they add to the overall quality and make the jeans feel like they’ll hold up over time. These jeans strike a nice balance between workwear toughness and casual style. They look good for everyday wear, but they’re also tough enough for more hands-on activities. For the price, they’re a great value, and I’d definitely recommend them to anyone looking for reliable, no-nonsense jeans.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on August 17, 2025
M
Verified Purchase
mark miller
San Leandro, US
★★★★★ 3
Delay was not as bad as originally told
Size: 33W x 34L, Color: Dark Stonewash
My original review was the pants were delayed 2 days with zero explanation other than sorry & was not posted because it did not meet the community standards, no cursing was included. They did jump through it & delivered the next day not 2 days. The pants were my 1st wranglers in a long time & apparently run larger than the Levi's that I normally wear so I returned for a smaller waist & length that came very quickly & seem good for the money.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on March 8, 2026
R
Verified Purchase
Russell Friedman
Lexington, US
★★★★★ 5
Excellent para Dunga
Size: 44W x 28L, Color: True Blue
Nice pair fit perfectly as advertised quality
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on May 14, 2026
T
Verified Purchase
Turtle Food
Port Orchard, US
★★★★★ 5
Big Guy comfort at Lil guy price.
Size: 58W x 30L, Color: Lieutenant
Being a bigger guy I can't go to Walmart or Target and find pants at me it seems to be a problem I have no matter where I go. And going to a big and tall store is extremely expensive. But I found these jeans here on Amazon and I ordered them not only did they fit comfortably I could breathe in them I could move I could bend I could squat I've even gone to work in these and been comfortable throughout the day they didn't cling to me they were the most comfortable pants I had in a long long time. I wore these jeans so often that finally after actually a couple of years I wore right through them I like ripped right out of them but the material with everything I do and I work in shipping and receiving the material lasted a good two and a half years with constant wear and tear so the material is strong it stretchy to go with moving around and breathed with me kept me warm on the Dock,and they made me look good. Washed them regularly and that didn't wear them out either. Overall for any big boys out there a 10/10.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on July 6, 2025

recommand products