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Ships within 48 hours · Estimated delivery Jul 15 - Jul 20
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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
4.3 ★★★★★
Based on 909 reviews
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Product Reviews
★★★★★ 5
Perfect for puppies and small dogs
Pattern Name: Cow Chew Toy Set
These toys are perfect for puppies and small dogs. They are well made and very cute. A good buy!
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Reviewed in the United States on January 31, 2026
★★★★★ 5
Great quality and made in the USA!
Pattern Name: Cow Chew Toy Set
I'm very happy with these toys. I can't stand these other toys that break easily and are from other countries that just don't have the same standards we do.
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Reviewed in the United States on March 20, 2026
★★★★★ 4
Great pack of toys for your fur-baby
Pattern Name: Cow Chew Toy Set
Our sweet Ziggy loves these toys. A couple he doesn’t pay much attention to, as he has favorites but there is a good variety and he’s enjoying all. The blue rubber toy with ball shapes in end you must watch them with, even with baby teeth he was able to chew ridges enough to get tiny bits of plastic/rubber off in about 10 minutes. He still plays with it outside. His favorite is the nubby blue/white bone, the rope/ring and snuggly plush. Good value!
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Reviewed in the United States on June 11, 2019
★★★★★ 5
Far Exceeded Expectations
Pattern Name: Cow Chew Toy Set
This was the first online purchase of dog toys that I made after we got our puppy. Purchase was made in August 2023. Currently February 2024.
Honestly, they were a little oversized for her at the beginning, but she still played with the stuffed cow (it was kind of her woobie) and some of the others.
Seven months in, here are her "reviews":
Round bone thing: Only clunker for our pup. She never took to that.
Cow plush squeaky: Loves it. Easy squeaker so a small puppy can still make it squeak, which they love because they think they're killing it.
Flat bone: Excellent for the devoted chewer. This has withstood many hours of gnawing with little evidence of wear. I do inspect it regularly because the hard plastic edging could be problematic if it starts to degrade. But it's holding up so far.
Blue double knot rope toy: This was one of her first chewers. She still loves it, though it does show wear because she is chewing off the tassles over time. Totally worth it.
Rubber ball with bell: She likes this, especially if someone throws it for her. From an owner standpoint, it gets slimy with saliva pretty quick, so I'm less enamored of it than she is. She hasn't used it as a chewer, though I'm sure some do. We leave it in her crate at night and that's how we know she's awake in the morning, because the bell tinkling as she rolls it around in the crate is a giveaway.
The rope ring thing is her A#1 very favorite thing, not just in this pack but among the wide variety of toys she has. She chews on it all the time and I'm back to order a new set of toys just to be sure we have one ready for the demise of the first. She loves to have it thrown, but she'll also just sit and chew on it. She also loves to do what my son calls "the spin cycle," in which she holds the rope in her mouth and throws the ring end all around as she spins. It's entertaining to watch. My aunt would have said, "Oh, look, she's playing with herself." To which my cousin would have replied, "No, Mom. Not WITH herself, BY herself!!!" Remembering which just entertains me all the more.
Now, a Boy Scout or sailor with knowledge of knots could re-string the one I have with new rope, I'm sure. And the next time I visit my dad, I'll ask hime to do just that. But for most people that's a bridge too far, so this company would be wise to sell just the rope pull toy. I haven't found a similar design on Amazon.
We have found this set to be a great value and highly recommend it.
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Reviewed in the United States on February 3, 2024
★★★★★ 5
AMAZING Toys for Teething and Mouthy Puppy
Pattern Name: Cow Chew Toy Set, Pattern Name: Cow Chew Toy Set
These toys have been a lifesaver for us with our 14 week old, 7.7 pound, King Charles Cavalier, Oliver. He is teething with his razor-sharp teeth and needs things to chew on that are not our hands, arms, clothes, chairs. He loves these toys! All of them have been enjoyed by him, but the Tug Ring is, by far, the most helpful with his teething. It is super durable and the perfect size for him. His runs around like a crazy-dog with it and then can settle himself chewing on it. The stuffed toy has been a comfort to him while sleeping and he also loves to sit and gnaw on the teething bone or run with the rope. The ball is a little large for him, but he still enjoys chasing it and scraping his teeth on it. We've had the toys a week and they have helped so much to provide appropriate chew things and distract him from inappropriate ones! The only other toy we have purchased is a smaller ball for Oliver to chase. These toys provide all we need!!!! Highly recommend!!!
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Reviewed in the United States on May 27, 2020
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