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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
4.4 ★★★★★
Based on 18 reviews
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Product Reviews
★★★★★ 1
Not for aggressive chewers!
Color: H) Infinity Ring, Color: H) Infinity Ring
Not for aggressive chewers! Done for in about two minutes. I unboxed this and tugged with my Mal for a but then let her have it. Within minutes she had chewed through it. Not worth the money.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on April 10, 2026
★★★★★ 4
Dog ball
Color: A) Small 2.5" Ball
My dog enjoys but smaller than expected
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on May 20, 2026
★★★★★ 5
Great tough ball
Color: A) Small 2.5" Ball
Great ball for dogs who like to destroy most any ball. Our girl loves this. Yay!!!
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on March 17, 2026
★★★★★ 3
Not Quite So Durable...
Color: B) Medium 3" Ball, Color: B) Medium 3" Ball
Maybe I have a SUPER aggressive chewer...he went through this ball in under a week. I originally bought the ball because of a review that stated the owner's Pitbull had the same ball for two years; not so much for my Rottweiler. He started chewing off and swallowing small crumbs from the ball within a day or two. By the end of the week, it was chunks so I had to toss it in the trash to prevent an intestinal obstruction. On the up side, my Rottweiler LOVED the ball while it lasted. However, I can't, in good conscience, give this ball a rave review based on this experience. Please take this review with a grain of salt as I have yet to find ANY toy that my boy won't DESTROY in a week or two. I hope that someone finds this informative when searching for chew toys for SUPER aggressive chewers like mine.
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Reviewed in the United States on March 16, 2026
★★★★★ 5
loud but in a good way
Size: 4.5"
Love these crazy loud squeeky balls. I bought two a bit too big but the dogs still love them. Yes, they will drive you insane but the dogs love them so much it's worth it watching the pups enjoy the balls. They are strong and safe as long as they aren't too small for your dogs mouth.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on May 2, 2026
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