Shipping Estimate
USA
- USA
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- USA
- CAN
Ships within 48 hours · Estimated delivery Jul 7 - Jul 12
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Description
Holley HP EFI ECU and Harness Kits 550-602NHP ECU AND HARNESS, LS1 6, NTK 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, LS1/6, NTK
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 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 NTK wideband 02 sensor designed to be used with GM LS1/LS6 engines with factory GM coils and a 24 tooth crank sensor
- The NTK Oxygen Sensor is recommended when using leaded or methanol fuels, high exhaust temperatures 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" 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
- Universal
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 | 550-602N |
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 1863 reviews
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Product Reviews
★★★★★ 5
Great sweater for winters in the Midwest
Color: Black, Size: X-Large
Love this sweater! I went back and got another color! The fit is true to size and very comfy. The button detail on the sleeves just adds a little pizazz. The weight of the sweater is perfect for winters in the Midwest.
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Reviewed in the United States on May 30, 2026
★★★★★ 5
Flattering fit
Color: Dark Green, Size: XX-Large
This sweater is thick and stretchy but holds a nice shape, and is flattering on the body. The sleeves are nice and long too, which I really appreciate, being a tall person... the button detail is a great addition. True to size. I haven't washed it yet, and I imagine, based on the kind of woolly knit it is, that this sweater will eventually pill... but for now I'm enjoying being cozy and stylish. The deep green color is almost black green. I LOVE IT.
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Reviewed in the United States on February 2, 2026
★★★★★ 5
Love it
Color: Dark Green, Size: Small
I got the dark green. Love the sweater and it's warm. I do layer the sweater as well. It is as pictured. Size is perfect to me. I like sweaters to be longer and a bit wider in case it is freezing and I need to layer it. This sweater is perfect for layering. It comes closer to my backside, it is a little wide and not snug, and I like that the sleeves come over my wrists
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Reviewed in the United States on February 7, 2026
★★★★★ 1
Still soft but looks terrible after 1 wash. Save your money
Color: White, Size: Small, Color: White, Size: Small
Update: sweater looked great when I received. After 1 wash it looks terrible. Looks like it’s been washed too many times, material fuzzy and piled. After wearing it once, it snagged and the knit pulled through. I would NOT recommend. I had such high hopes. Save your money.
Very nice sweater, especially for the price! I love the details of the buttons on the sleeves. It is SO soft. It’s not super thick as I can see my skin through it when pressing my hand up against fabric. However, it’s not see through when wearing it. It’ll be perfect in cooler weather and perfect in the winter with a coat but won’t cause me to overheat when in a heated environment. I do feel like it runs big. I could have sized down a size. Although I’m not sure if it’ll shrink after a wash or two.
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Reviewed in the United States on September 22, 2025
★★★★★ 3
Disappointed.
Color: Blue, Size: Large, Color: Blue, Size: Large
This sweater is so comfortable and very soft. It fits well in a flattering, oversized way. But after one wash it is pilled everywhere which makes it look old and shabby. It’s at a price point where I feel compelled to return it.
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Reviewed in the United States on January 10, 2026
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