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Description
Holley HP EFI ECU and Harness Kits 550-602HP ECU AND HARNESS LS1 & LS6 Looking for a plug and play kit for your GM LS engine? The HP ECU allows you to accurately control the fuel and ignition of your engine plus much more! Got a stock LS engine? Simply download a base map and you're on your way. Got a turbocharged, nitrous fed LS engine on water meth? This HP EFI kit can control that too! Stop reflashing your factory ECU every time you make a performance modification. Get Holley EFI today!
HP ECU AND HARNESS LS1 & LS6Looking for a plug and play kit for your GM LS engine? The HP ECU allows you to accurately control the fuel and ignition of your engine plus much more! Got a stock LS engine? Simply download a base map and you're on your way. Got a turbocharged, nitrous fed LS engine on water/meth? This HP EFI kit can control that too! Stop re–flashing your factory ECU every time you make a performance modification. Get Holley EFI today!
Features:
- Simple Installation - Plug and Play control of GM LS1/LS6 engines. Just plug the harness into your factory sensors, wire the power and grounds and you are ready to take complete control of your LS engine
- More Functionality - Provides significantly more functionality than OEM or other competitive ECUs (boost control, nitrous control, water/meth injection, plus a host of additional inputs and outputs to control fans, pumps, relays etc.)
- Easy To Use - Laptop programmable ECU includes a variety of base maps that will have you hitting the cruise or track in no time
- Ideal For Everything - including stock 5.3L engine swaps or all out, 3,000+ horsepower race cars that need a simple and powerful ECU and harness solution
- Industry Leading Self Tuning Fuel Strategy - means less time tuning and more time enjoying the power of your LS vehicle
- Kit includes ECU, harness, communication cable, software and and Bosch wideband 02 sensor designed to be used with GM LS1/LS6 engines with factory GM coils and a 24 tooth crank sensor
- ECU is fully potted and can be mounted in the engine compartment or interior
- Sealed automotive and marine grade connectors
- 1-5 Bar MAP sensor capability
- Optional plug and play hand-held programmer, 5.7" touchscreen and digital gauges are available for ultimate control and vehicle monitoring
- ECU is certified to ISO 8846, SAE J1171 & United States Coast Guard Requirements for Ignition Protection & Fire Resistance
- For a full list of advanced features such as boost, nitrous, water/meth, individual cylinder control and more click the document icon under the product image!
Application
-
Univesal
Specs
| Brand | Holley EFI |
|---|---|
| Crank Reluctor | 24x |
| Emission Code | 4 |
| Ignition Type | GM LS 24x |
| Injector Connector | Jetronic / Minitimer (Bosch) |
| Product Type | HP EFI Kit |
| Part Number | 550-602 |
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
4.7 ★★★★★
Based on 16 reviews
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Product Reviews
★★★★★ 5
The only one I'll use!
As the title says, this is the brand to get!! It's fast-acting, doesn't give me weird dreams like some do, and I never wake up feeling groggy.
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Reviewed in the United States on March 13, 2025
★★★★★ 5
Works wonders
I've been buying these for well over a year now as Subscribe and Save. I work 12 hour overnights as a nurse. My sleep schedule normally gets messed up. I would have no problem falling asleep but would wake up only a few hours later which is not good when you have work again that night. We buy these on Amazon due to the great price and the fact that they are extended release which helps keep me asleep longer. When I take 1 or 2 of them, I am able to sleep about 7-8 hours which is great. I take this both when I sleep during the day and sleep during the night. It helps me sleep no matter when and I am able to adjust my sleep schedule often. I have recommended them to many.
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Reviewed in the United States on January 10, 2013
★★★★★ 4
Works quite well, dose still a bit high for me
Used to take the Natrol 5mg slow release, now that I can compare these 2, I love this more. It doesn't make me feel too edgy, it's quite relaxing actually. I still have to halve the dose as the full dose makes me groggy the next day. Where the Natrol gave me very vivid, but not unpleasant dreams, these don't make me dream as vividly. It does take a bit longer to get me to sleep, but once asleep, your asleep. Highly recommend, once I finish this bottle, I'd get the 2mg tr next time, as a lower dose works better for me.
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Reviewed in the United States on July 10, 2014
★★★★★ 5
Excelente Muy Satisfecho
Servicio excepcional, cuidadoso, el producto muy bien empacado. Y el tiempo de entrega fue el acordado. Y del producto ni hablar, excelente.
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Reviewed in the United States on February 3, 2026
★★★★★ 5
seems to work just fine
Helps me sleep. I also use Mg, B complex and medical cannabis oil before bed. My sleep isn't great otherwise here in the good ol' USA (unlike in Europe where I sometimes go for complicated issues/not vacation; which indicates issues with the much higher radiofrequency exposure allowed in the US than in the European country where I sleep like a happy baby). Just wait for 5G, then I probably need to reinvent my sleep protocol if I want to get any rest. But well, with the 5G impact on the biosphere, we may not be here much longer then. That means we better stop 5G before it's all roleld out.
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Reviewed in the United States on August 2, 2019