SKU: 50644243334

Holley HP EFI ECU and Harness Kits 550-603

Sale price$1282.47 Regular price$1424.97
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  • USA
  • CAN

Ships within 48 hours · Estimated delivery Sep 17 - Sep 22

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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:
  1. 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
SKU: 50644243334

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Cynthia Bullock
Omaha, US
★★★★★ 5
Great Puppy Teething Toys
Color: Pink1, Color: Pink1
Great items, my pup Dolly has toys to not bite my hands!
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Reviewed in the United States on June 11, 2026
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MoeCandi
Louisville, US
★★★★★ 5
She loves them!
These are perfect for my teething puppy! She likes to play with a couple of them more than the others, but they are very durable and cute.. the strings on stuff she already untied and played with those as well. Good purchase, I think these will last a long time!
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Reviewed in the United States on September 1, 2024
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Penelope Hodge
Omaha, US
★★★★★ 5
Very impressed with this product.
This is perfect! For tiny teether's. The value is perfect, it's safety is good., The toy quality is well made. Just perfect for smaller puppies.
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Reviewed in the United States on August 7, 2025
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Devon C.
West Palm Beach, US
★★★★★ 4
Perfect
Our puppy is teething, and these are so helpful during this time for her! The only issue are the fabric strips come off, and we have to throw them away so she dont try to eat them!!
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Reviewed in the United States on September 16, 2023
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Scottish Kathleen
San Leandro, US
★★★★★ 5
Your puppy will love these!
My little dog Loves these! Excellent quality. GREAT BUY!
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Reviewed in the United States on November 14, 2025

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