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Ships within 48 hours · Estimated delivery Jul 7 - Jul 12
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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:
- 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 385 reviews
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Product Reviews
★★★★★ 5
Finos y cómodos
Size: 9, Color: Taupe
Tal cual muestra la descripción y las fotos. Cumplió nuestra espectativas la compra. Finos y cómodos
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on April 26, 2026
★★★★★ 5
For slim feet
Size: 13, Color: Black
Had to send both pair back. Nice shoe but their size 12 was to narrow for my feet. Pitty, as they looked and felt great in the box. Got a slender foot? Try these.
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Reviewed in the United States on March 16, 2026
★★★★★ 1
Cheap quality
Size: 11, Color: Cognac
I hardly ever leave reviews because most everything is as expected. However these shoes, although they look nice and if you apply a polish they look even better, just aren’t worth it. They are offered at a good price, but don’t live up to even that cost.
As others mentioned the stitching came undone within the 2nd day of use. I had to break out the needle to put the thread back in so they wouldn’t fall apart. That problem fixed didn’t stop the issues. Within a couple more weeks of use the leather started peeling on the tip of the shoes and thus lost all future use.
You would be better off buying a more expensive pair with better quality leather and stitching.
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Reviewed in the United States on January 3, 2026
★★★★★ 5
Exactly What I Was Looking For
Size: 8.5, Color: Cognac
Love these shoes and were exactly what I was looking for. Stylish and go with so many different styles plus they’re extremely comfortable and lightweight.
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Reviewed in the United States on March 19, 2026
★★★★★ 5
Would recommend
These shoes have quickly become my go-to shoes for everyday wear. First off, the fit and comfort are fantastic right out of the box — no breaking-in period needed. They feel supportive without being stiff, and I can wear them all day without my feet getting tired.
I really like the look too. They strike a nice balance between casual and polished, so they work with jeans, chinos, or even smart-casual outfits. The design isn’t too loud or flashy, but they still look sharp enough for dinners, errands, or work-from-home Zoom calls.
One thing I love is how easy they are to slip on and off. No laces to fuss with, and the elastic stretch makes getting them on quick and easy — perfect for mornings when I’m rushing out the door.
They also feel versatile. I’ve worn them for walking around town, to casual office days, and even a weekend brunch, and they’ve suited every situation without looking out of place.
Overall the quality feels solid for the price — good stitching, durable materials, and so far no signs of wear after a few weeks of frequent use. Comfort, style, and convenience all in one pair.
If you want casual loafers that look good and feel great without any fuss, these are definitely worth checking out.
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Reviewed in the United States on February 3, 2026