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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.
- 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 28 reviews
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Product Reviews
★★★★★ 5
Cheaper & Higher Quality Than OEM Filters
Size: 9.3" x 9.7" x 1.8"
This Bosch Filter costs less than an OEM Filter and is significantly better because it's a HEPA filter unlike the cheap filters that most automotive manufacturers use. Can't go wrong with this!
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on May 26, 2026
★★★★★ 5
You really need to change this filter !!!!
Size: 9.3" x 9.7" x 1.8"
This is a great cabin filter for her 2013 Honda CR-V... It was relatively easy to get the glove box down just enough to allow me to get my hands on the cabin filter cover, and pull it out... It was so dirty!!! The new one immediately made the air coming into the car, so much nicer to breathe.... Great filter...Perfect fit.... Thanks, Bosch !!!
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on February 7, 2026
★★★★★ 5
Good deal
Good price for a good starter, arrived quicker than anticipated, well packaged, easy install and works as it should.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on August 19, 2025
★★★★★ 5
Works fine 3 months in
Installed a few months ago, before the winter. I was chasing a no-start after replacing the old battery. We've seen single digit temps in the meantime and it is working well. The fit is perfect in a 2010 focus. If you can slide it in from the side and not drop it in from the top, you can replace it without taking off the intake manifold. There are useful videos online showing this. Good luck!
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on December 28, 2025
★★★★★ 1
Will be returned as soon as I have a replacement.
When engine is cold starter works fine with engine is hot. It will free wheel the starter motor, but not kick the starter gear into the ring gear on the motor. Watch video and listen it actually did it twice at this location but I didn’t catch the first one on the video.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on December 25, 2025
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