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Description
Holley HP EFI ECU and Harness Kits 550-603HP ECU AND HARNESS LS2 & LS7 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! Features: Simple Installation Plug and Play control of GM LS2 LS3 LS7 engines. Just plug the harness into
HP ECU AND HARNESS LS2 & LS7
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!
Features:
- Simple Installation - Plug and Play control of GM LS2/LS3/LS7 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, USCAR (EV6 Style) injector connectors, and Bosch wideband O2 sensor, designed to be used with GM LS2/LS3/LS7 engines with factory GM coils and a 58 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" touch screen 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
- Universal
Specs
| Brand | Holley EFI |
|---|---|
| Crank Reluctor | 58x |
| Emission Code | 4 |
| Ignition Type | GM LS 58x |
| Injector Connector | USCAR (EV6) |
| Product Type | HP EFI Kit |
| Part Number | 550-603 |
Shipping Notes
- Free Standard Shipping on $100+ Orders to the USA.
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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
4.1 ★★★★★
Based on 24 reviews
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Product Reviews
★★★★★ 4
Interesting book.
Format: Paperback
No more surprise very useful book. You can even use it and ask clients about their symptoms to confirm the suspected diagnosis.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on October 26, 2025
★★★★★ 5
perfect
Format: Paperback
i use this all the time for on the go for home visits. super helpful for immediate psychoeducation with clients to explain their diagnoses reflecting their symptoms.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on October 24, 2025
★★★★★ 5
Nice quick reference to have
Format: Paperback
I have the full blown one I keep in my home office, and have another position where I don’t diagnose often, but keep this guy as a quick reference. My second position is working with mostly people who aren’t MH professionals, and this is just helpful for a general overview/fast refresher
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on August 31, 2025
★★★★★ 5
Made Med-Surg Less Overwhelming
Format: Kindle
This book broke down complicated nursing topics in a way that actually felt manageable. The practice questions and real-world examples helped me feel more confident and less anxious while studying for exams.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on May 26, 2026
★★★★★ 1
Chaotic Table of Contents, Chapters and pages in TOC are incorrect
Format: Paperback
I just opened it and the Table of Contents is "Chaos." The Chapters and pages in the Table of Contents (TOC) do not reflect the actual chapters and pages in the book. For example, TOC shows Chapter 8 in page 94. But if you turn to page 94, it is the second page of Chapter 9. Will continue to update this review when I start to read the book. For now, it is a "1" for the Table of Contents.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on April 28, 2026
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