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Description
HP EFI ECU & Harness Kits - 550-603NOverview: 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
Overview:
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 NTK wideband O2 sensor, designed to be used with GM LS2/LS3/LS7 engines with factory GM coils and a 58 tooth crank sensor
- The NTK Oxygen Sensor is recommended when using leaded or methanol fuels, high exhaust and forced induction applications or for highest precision feedback
- 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:
| Year | Make | Model | Submodel | Engine Size |
|---|---|---|---|---|
| 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 |
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
4.2 ★★★★★
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Product Reviews
★★★★★ 5
Great water flosser
Color: Pink+purple
Got it for my 10 year old with braces and it works great! She even takes it to sleepovers! It’s so portable and the travel safe design is great. It’s a very reasonable price as well. Would highly recommend
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Reviewed in the United States on December 2, 2025
★★★★★ 5
Good buy
Color: Pink+purple
Kids love it. Still works great
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Reviewed in the United States on June 2, 2026
★★★★★ 4
Works great.
Color: Blue+red
I love how easy this children’s dental floss is. My child with ASD is able to use with little to no help. it’s been years trying to get my child with sensory sensitivities to floss or brush teeth without a HUGE STRUGGLE, however this is very gentle and something that makes our oral health care routine smoother. ( if you know, you know!!) It is very similar to the viral “ usmile” adult version water flossers. My only complaint/issue with this is that it collapse pretty easily and sometimes it’s hard to keep in the locked position while flossing teeth. Overall a good product, and recommend.?
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Reviewed in the United States on January 18, 2026
★★★★★ 5
Good for kids
Color: Blue+red
A little powerful for my 8 year old at first but after he got the hang of it, he loves using it.
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Reviewed in the United States on May 7, 2026
★★★★★ 5
Great for dental appliances
Color: Pink+purple
My daughter has a dental appliance that can get food caught in it. We were told to try a water flosser to get the trapped food out. This has done exactly that. Very happy with it.
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Reviewed in the United States on January 7, 2026