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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
4.7 ★★★★★
Based on 19 reviews
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Product Reviews
★★★★★ 5
I will buy this planner every year!
Format: Book Supplement
I had a 2025 Old Farmers Almanac Planner and loved it. I had to get the 2026. This planner is perfect for me. Shows the month at a glance, but then has the day pages where you can put plenty of notes!
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on December 24, 2025
★★★★★ 4
A nice themed planner
Format: Book Supplement
Not a garden/farming planner. Just a regular planner with some Old Farmers Almanac rubbed on it. Really well made and nice looking but not really super special or helpful for farming or gardening.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on November 22, 2025
★★★★★ 5
Got one last year for the first time and I'm hooked!
Format: Book Supplement
I love this planner. And the calendar. I want very specific things in my planner and this checks all the boxes. Very detailed. Love all of the daily facts. Got one last year for the first time and I'm hooked!
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on May 30, 2026
★★★★★ 5
Great Book
Format: Book Supplement
Been buying this Planner since 2022. First year I bought it for myself. 2nd year myself & my bestie. 3rd year myself, bestie & another friend. I’m sure you get the idea. 😁 I keep up with daily weather predictions on the calendar page & daily activities, of any type, in the days of the week section. I can see when I planted a crop or when I SWR the bed (for those not in the know it means strip, wash & remake the bed). My youngest daughter got a real kick out of that one. Told her when I passed she could read them all & try to figure out what the heck I was talking about. *LOL* Great book, beautiful renderings & interesting tips & notations.
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Reviewed in the United States on January 4, 2026
★★★★★ 5
Very organized planners
Format: Book Supplement
Beautiful planner
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on February 11, 2026
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