SKU: 44499070246

Holley HP EFI ECU & Harness Kit (HO550-601)

Sale price$2636.55 Regular price$2929.50
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Description

Holley HP EFI ECU & Harness Kit (HO550-601)HO550 601 HP EFI ECU WITH HARNESS Suit GM TPI & Holley Stealth Ram Part Number: HO550 601 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

HO550-601 - HP EFI ECU WITH HARNESS

Suit GM TPI & Holley Stealth Ram

Part Number: HO550-601

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.
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/Meth

Shipping Notes
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Exchange/Return Notes
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SKU: 44499070246

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4.3 ★★★★★
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JmeRed
Dallas, US
★★★★★ 5
This product is unbelievable! There is nothing else like it!!!
I've tried a couple different spray tanners to cut back on tanning beds and be healthy about being bronze. This one goes aboveeeeeeeee and beyond anything I've ever tried. I almost don't want to leave this review so no one buys these and I can keep the secret to myself haha. The mist that comes out of these is like a professional quality tanning spray. It's very fine, almost like a cloud instead of a spray. Which makes it a lotttt easier to get an even coat without any missed spots. The color of this spray is different than anything I've tried too. Most sprays have an orangey brown color but this is a deep greenish brown (green+red=brown) *the red being the pink tones in your skin. I don't mean to say that this comes out greenish, just that it is farrr from the fake orange color I usually see. The other person said they rub theirs in a bit but I found that letting the mist lay where it lands and dry as is gives me a better all over color.
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Reviewed in the United States on May 16, 2012
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Dayna Spielman
Draper, US
★★★★★ 5
Best tanning spray
This is my favorite tanning spray. I purchase it on auto ship. It’s gives an even realistic tan that is easy to use. The only negative is that some of the spray nozzles clog or are defective but I can usually change them with one the sprays mist.
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Reviewed in the United States on May 23, 2024
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CosmicAddiction
Omaha, US
★★★★★ 5
What a find!
Color: PDRN 25%
Good stuff! My skin healed ULTRA fast with this!! I can really tell it is good stuff! Plus, it has that “bio” smell that means it’s real. The formula is a little oily as opposed to watery. Just FYI I think serum slightly thicker is better.
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Reviewed in the United States on May 19, 2026
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ADO
Birmingham, US
★★★★★ 5
Oopsy Daisy, bad for not reading directions!
Color: PDRN 25%
Oops 😬, I forgot to mix this PDRN serum with my hyaluronic serum before applying on my skin. Instead I have been applying it directly on my face 2x daily. I have noticed major improvement on my skin. My skin is dewy, bright, and flawless. Fortunately, I did not experience any skin reactions the undiluted product. I will come back and stock up on these bottles to mix with hyaluronic serum for microneedling.
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Reviewed in the United States on December 26, 2025
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Boston
Phoenix, US
★★★★★ 4
The Skin Regenerator Your Routine Is Missing
Color: PDRN 25%
If you've been dealing with dull, dehydrated skin or feel like your usual creams just aren't cutting it anymore, the Salmon DNA PDRN 250,000 ppm Concentrate might be the missing piece. I started using this booster three months ago, and it has genuinely transformed the texture and bounce of my skin. What problem does this solve? As we age or expose our skin to environmental stress, our natural cell regeneration slows down, leading to dullness, loss of firmness, fine lines, and a damaged moisture barrier. This PDRN concentrate essentially acts as a cellular "wake-up call." Salmon DNA shares a remarkably high biocompatibility with human skin, helping to repair DNA damage, reignite collagen production, and speed up the skin's natural healing process. Features & Benefits · Regenerative Power: Packed with 25% (250,000 ppm) PDRN (Polydeoxyribonucleotide) to repair and rejuvenate. · Wrinkle & Texture Refinement: Helps improve elasticity and reduce fine lines for smoother, more resilient skin. · Hydration & Barrier Support: Formulated with Sodium DNA and Panthenol to deeply replenish moisture and soothe sensitivity. · Booster Format: A versatile concentrate you mix with your moisturizer or serum to amplify your entire routine. · Enhanced Complex: Includes EGF (Epidermal Growth Factor) and Peptides for added collagen support. Pros · ✅ High concentration of active ingredients for noticeable results. · ✅ Excellent for post-procedure skin (non-irritating after microneedling). · ✅ Improves overall skin health, not just surface appearance. · ✅ Suitable for all skin types looking for anti-aging or hydration. Cons · ❌ Texture can be sticky – it leaves a slight residue on your fingers and face that takes a few minutes to absorb. · ❌ Requires consistency – results are not instantaneous and need regular use to build. · ❌ The concept of "salmon DNA" might feel unusual to some, though it's highly effective and dermatologist-backed. Final Verdict This isn't a quick-fix product, but if you stick with it, the reward is skin that looks plumper, healthier, and more resilient. It’s like sending your skin into a repair shop. Best for anyone who has hit a plateau with their current anti-aging routine or who wants to actively strengthen their skin's foundation.
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Reviewed in the United States on May 21, 2026

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