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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
4.4 ★★★★★
Based on 11 reviews
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Product Reviews
★★★★★ 5
Keeps pups busy, good for chewers.
Size: Medium, Color: Antler
My dogs love this product. Keeps them busy and it lasts. Just watch out for your feet when they drop it! Heavy
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Reviewed in the United States on May 17, 2026
★★★★★ 5
Power Chewer Loves This!
Size: Medium, Color: Antler
This is my dog's new favorite chew! She loves that she can hold it in her paws. I think she really loves the taste and texture of it. I don't give her antlers as I have heard too many horror stories about broken teeth. I also don't give her nylon toys as I have also heard a lot of horror stories of broken teeth as well as concerns about them digesting the plastic. This is between antlers and bully sticks, which is perfect for a power chewer. I feel comfortable with her eating the pieces that flake off this toy. She loves chewing and she will default to this toy when she wants to help calm down. I don't notice much of a smell. It does flake, but not enough I will even take a star off. Plus, it's plant based and vacuums up easily once dried. It doesn't capture her attention as much as bully sticks or beef cheek chews, but it's much less expensive over time and doesn't stink up our living room! She will also always pick this over any of her rubber chews. Great product and recommend it for all the power chewers.
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Reviewed in the United States on September 23, 2025
★★★★★ 3
Crumbly, odd texture
Size: Large, Color: Duo Pack
Neither of my dogs were very interested in these. They did chew on the antler-shaped versions more so than the infinity-style versions. When they did chew on these, they didn’t hold up well or last long. These have a strange, crumbly texture when chewed. You’ll find bits and pieces of these chews where the dogs have been chewing. Will not be reordering.
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Reviewed in the United States on April 5, 2026
★★★★★ 4
This appears to be a good alternative to the hard plastic chew toys.
Size: Large, Color: Duo Pack
My dog is a heavy chewer. I decided to try this brand out after using a different brand for quite awhile. while my dog seems to like it and carries it around (the pretzel shaped one) he doesn't seem to attack it as whole heartedly as his old brand, I'm thinking it might be the shape, we will see when he wears it out and I switch him to the antler shape. What I like most about it is it doesn't tear my hand up like the other brand did after he had been chewing it for awhile. While it is wearing down some it seems to do it in a more mild manner. Since we haven't had it long I would give this 3.5 stars because I don't know if it will last as long and not sure f it is just the shape that has him more mellow with it.
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Reviewed in the United States on January 27, 2026
★★★★★ 5
Choose your shape
Size: Medium, Color: Duo Pack
I love the idea of the dogs not eating nylabone plastic so have been searching for "healthier" options that last for heavy chewers. Two German Sherpherds, they are not big fans of the circular shaped toy but love the antler shaped one and even with both chewing on it, has not been destroyed yet and is not cutting their gums open. I am not finding pieces laying in the carpet. Recommend this
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Reviewed in the United States on May 29, 2026