SKU: 34360476229

HP EFI ECU & Harness Kits - 550-601N

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 Aug 19 - Aug 24

Promo Codes Available:

For Your Every Summer RSVP, with Code: SUMMER15

Description

HP EFI ECU & Harness Kits - 550-601NOverview: 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

Overview:

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:

  • NEW V2 SOFTWARE FEATURES
  • “Quick Start” ignition and fueling strategy for LS x Engines
  • Data Logger. Scalable axes, Smoothing, Multiple graph view ability, Pre-defined notes fields and many more
  • Strip Chart Real-Time Data Viewer
  • Integrated Boost Control - Boost vs Time, Boost vs Gear (Time or RPM), Boost vs RPM, Boost vs Speed, Launch control. Boost launch builder, Over-boost safeties, Boost scramble
  • Traction Control - Power reduction via timing, nitrous percentage or boost (Requires Davis Technologies Holley Module)
  • “Quick Start” fueling for all engines
  • Option for VE based fueling strategy
  • Fuel Map and Learn Function Smoothing
  • Configurable User Password Protection
  • Fully Configurable lap top Gauge Panel
  • 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 for Water/Meth tuning precision unmatched in the industry

Application:

Year Make Model Submodel Engine Size
Universal

Specs:

Brand Holley EFI
Emission Code 3
Ignition Type Coil - (No Timing Control)
Ignition Type GM HEI Small Cap
Ignition Type Holley Dual Sync Distributor
Injector Connector Jetronic / Minitimer (Bosch)
Product Type HP EFI Kit
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: 34360476229

Discover Niche Categories That Outsell

Top-Converting Item to Boost Your Average Order

4.2 ★★★★★
Based on 7 reviews
Sort
Highest Rating
Newest First
Oldest First
Product Reviews
L
Verified Purchase
Lo
Pawtucket, US
★★★★★ 5
Great shelves
Size: 24 Inch, Color: White
Easy to assemble and comes with everything you need for drywall or wood. Nice color and texture and comes with stickers to hide the holes underneath. I bought two sets of three. These are very long, so I recommend just using two at a time.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on February 8, 2026
T
Verified Purchase
Tarra
Omaha, US
★★★★★ 5
great shelves
Color: C. White - Modern Minimalist Style, Number Of Shelves: 3, Size: 36inches
These are a a great set of floating shelves! They were easy to install, feel sturdy, and look clean and modern on the wall. The set of three is perfect for displaying decor, photos, plants or small storage items while adding extra space without taking up room. Great quality, stylish, and a simple way to upgrade any space. They work perfect for my figurines to be displayed.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on May 19, 2026
K
Verified Purchase
KadeeH
Birmingham, US
★★★★★ 5
Great shelves
Color: A. Black - Universal Classic Style, Number Of Shelves: 3, Size: 22.5inches
Easy to hang and look great in my office. I love the little divot along the edge. Helps to keep pictures from sliding.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on May 29, 2026
C
Verified Purchase
Crystal
Lowell, US
★★★★★ 5
Exactly what I needed for my bathroom refresh.
Color: B. Rustic Brown - Americana Farmhouse Style, Number Of Shelves: 2, Size: 22.5inches, Color: B. Rustic Brown - Americana Farmhouse Style, Number Of Shelves: 2, Size: 22.5inches
I bought these floating shelves in the color Rustic Brown to replace a bulky storage shelf that was making my bathroom feel cramped, and they completely transformed the space. The wood finish looks much more expensive than I expected, and once installed they gave the bathroom a clean, modern, spa-like feel without taking up visual space. Installation was straightforward overall. I mounted one screw in the center into a stud and used drywall anchors for the remaining hardware, and the shelves feel very sturdy. They sit flush against the wall and don’t sag or wobble. I especially love how slim they are while still being deep enough to hold everyday bathroom items, decor, candles, skincare, and small baskets. The color worked perfectly with my bathroom vanity and mirror trim, and the floating design instantly made the room look more organized and intentional. Huge upgrade for a small space. Definitely recommend if you want functional storage that also looks elevated and minimalist.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on May 30, 2026
A
Verified Purchase
Amazon Customer
Chelsea, US
★★★★★ 4
Good Shelves
Color: B. Rustic Brown - Americana Farmhouse Style, Number Of Shelves: 3, Size: 22.5inches
These shelves are really nice quality and look as advertised. The hardware included was great quality, metal drywall anchors and good screws. They were easy to install, and make even/level with each other. My only gripe is the price, but I'm very satisfied with the product overall.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on April 12, 2026

recommand products