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Ships within 48 hours · Estimated delivery Jul 13 - Jul 18
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Description
HP EFI ECU & Harness Kits - 550-601Overview: 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:
- 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
4.3 ★★★★★
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Product Reviews
★★★★★ 4
Beautiful design
Simple, functional and beautifully designed, I'm glad I bought it.
(not a five starts just because I thought it was higher, but again, my fault for not reviewing the specs first)
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Reviewed in the United States on October 29, 2024
★★★★★ 5
Phenomenal Stand!
I Have 5 Of These Top Shelve Laptop Stands I Use For Various Projects I Work On While Home.
Mostly Music Editing & DJing! These Stands Are Most Durable!!
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Reviewed in the United States on March 21, 2026
★★★★★ 5
Not Your Average Laptop Stand
One of the things that I always worry about with stands for my computer is how sturdy they will be. If they aren't sturdy, they aren't really worth having. This is super sturdy -- I don't feel any bounce or flex when I work on it. It's also super well made and looks good sitting on my desk. Both of those things make this one of the best stands that I've used. I just wish it were adjustable.
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Reviewed in the United States on September 7, 2025
★★★★★ 5
I’m really impressed with these 12-inch Heavy Duty Floating Shelf Brackets!
Size: 12 Inch, Style: Black 6Pack
I recently installed them in my living room to hold some books and decorative items, and they’ve been fantastic. The brackets feel extremely solid and well-made — the 1/5-inch thick iron gives them a sturdy, industrial look and they hold the shelves without any wobbling or sagging. I also love the sleek black finish; it looks modern and stylish, and it really complements my décor.
Installation was straightforward and stress-free because the set comes with screws, anchors, and a lever — everything I needed to get the shelves up securely. The pack of six brackets is great because it gave me enough for multiple shelves and even an extra in case I need it.
The only minor thing to note is that aligning the brackets perfectly requires a bit of patience, but once leveled, they hold like a dream.
Overall, these brackets are a great combination of strength, style, and value. They’ve made my shelves look clean and professional, and I feel confident they’ll last for years. Highly recommend for anyone looking for heavy-duty, attractive shelf support!
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Reviewed in the United States on December 7, 2025
★★★★★ 5
High quality look for office
Size: 10 Inch, Style: Black 4Pack, Size: 10 Inch, Style: Black 4Pack
These brackets were exactly what I was looking for. Very solid construction, clean powder-coated finish, and they gave the shelves a modern industrial look without being bulky. Installation was straightforward, and once mounted into studs they felt extremely sturdy.
I used them for floating wood shelves and was honestly impressed with how much weight they can handle without flexing. The black finish also matched perfectly with the rest of the room hardware.
For the price, these are a great value and look far more expensive than they are. Would definitely buy again for future projects.
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Reviewed in the United States on May 1, 2026