SKU: 34360476229

HP EFI ECU & Harness Kits - 550-601N

Sale price$1349.97 Regular price$1499.97
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Ships within 48 hours · Estimated delivery Jul 11 - Jul 16

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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:
  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

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Akeem
Whiting, US
★★★★★ 5
Comfortable and stays cool
Color: White-cooling Basic, Size: Queen(Pack of 1)
Great pillow. When i opened it, i noticed a strange smell, i assumed its the smell of whatever they use to make the pillow stay cool. You have to fluff it for a good amount of time to make sure the cooling agent spreads well in the foam. Is what i assumed atleast. Its a perfect amount of softness for me. Pair it with some bamboo pillow cases and you got a good night of sleep
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Reviewed in the United States on May 9, 2026
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Kim Groetsch
Lexington, US
★★★★★ 5
BEST, MOST COMFORTABLE PILLOWS EVER!
Color: White-cooling Basic, Size: Queen(Pack of 2)
I've used others.BEST PILLOWS EVER! Firm, cooling and supportive. LOVE THESE!
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Reviewed in the United States on May 28, 2026
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Juanita
Louisville, US
★★★★★ 4
Comfortable and Supportive, but Adjust the Filling
Color: White-cooling Basic, Size: Queen(Pack of 2), Color: White-cooling Basic, Size: Queen(Pack of 2)
I’m very happy with this pillow. The size is big and it feels soft while still providing good support, perfect for midnight scrolling on TikTok. One thing to keep in mind is that it can feel a little too tall if you use all of the filling that comes with it. The good news is that you can easily adjust the amount of filling to find the height that works best for your sleeping position. Once I customized it, it was much more comfortable. Overall, great quality, comfortable, and worth the purchase.
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Reviewed in the United States on June 3, 2026
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Love Leigh Angel
Omaha, US
★★★★★ 5
BEST PILLOWS EVER!!!
Color: White-cooling Basic, Size: Queen(Pack of 2)
I am very picky with my pillows because I have a bad neck and I can never seem to find a good pillow. But I tried this pillow because it had everything I was looking for and the price was great! You get two of them and they are absolutely awesome.! normally I would need to lay on two pillows to try and get comfortable but with these pillows I just lay on one and I wake up with no neck pain. They really have a nice cooling effect. They actually puff up immediately after opening them. All you have to do is just shake them up and the pillow just puffs straight up.. It comes with extra cushioning if you want it to make it firmer and if you don’t want it as firm as it is, you can actually take some out. It really is such a beautiful pillow. It’s perfect in every way to me being such a picky pillow person. You just lay your head down on it and it forms around your neck and your head and when you get up, it goes right back to its normal form. It doesn’t get flat and I love it. I completely recommend this to anyone who is a person who has a hard time finding a really good pillow.
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Reviewed in the United States on April 12, 2026
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$@[)E
Lexington, US
★★★★★ 5
Top of the line, best pillows Ive ever had
Color: White-cooling Basic, Size: Queen(Pack of 2)
These pillows are top of the line! I bought them in 2024 and they are still fluffy. When they lose a little fluff, you just punch em around a little bit and voila, like new again. They have kept their shape cery well and do great for cooling. I haven't had to add more filling yet either. I just laid my head on one and thought, I need to do a review cause everytime i lay on these pillows its like clouds. My head is heavy and this is relief :-D
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Reviewed in the United States on May 21, 2026

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