SKU: 14188638123

Holley HP EFI ECU and Harness Kits 550-603

Sale price$1282.47 Regular price$1424.97
Save 10%

Pay in installments of $356.24 with ShopPay, AfterPay and Klarna

Shipping Estimate
USA
  • USA
  • CAN

Ships within 48 hours · Estimated delivery Oct 11 - Oct 16

Promo Codes Available:

For Your Every Summer RSVP, with Code: SUMMER15

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: 14188638123

Discover Niche Categories That Outsell

Top-Converting Item to Boost Your Average Order

4.4 ★★★★★
Based on 30 reviews
Sort
Highest Rating
Newest First
Oldest First
Product Reviews
L
Verified Purchase
Lacy Henry
Bozeman, US
★★★★★ 3
Spray stops working
Size: 5 Ounce (Pack of 2)
I’ve been buying this product for awhile and keep experiencing issues. It protects your skin well but is sometimes hard to spray and half the time the nozzle stops working while there is still product in the bottle.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on November 27, 2024
A
Verified Purchase
Alison
Houston, US
★★★★★ 5
Perfect
Size: 5 Ounce (Pack of 2)
Goes on easy, protects well from the sun.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on September 10, 2024
K
Verified Purchase
Kim Haldrup
Whiting, US
★★★★★ 5
Goes on clear, superior protection and moisture to skin
Size: 3 Fl Oz (Pack of 2)
Love this moisturizing formula, beachy scent and really protective. I used in South Pacific and needed a reliable sunscreen to last and stay protective while in water. This one delivers and size is TSA compliant.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on January 24, 2026
S
Verified Purchase
Shelly
Belleville, US
★★★★★ 5
Terrific Quality
Size: 3 Fl Oz (Pack of 2)
Best suntan lotion. I’ve used this brand for a couple of years now and am impressed at how well it works. I have fair skin and it truly helps so I don't get burned like I used to with other brands.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on May 6, 2026
M
Verified Purchase
Minnesott Sailor
Alexandria, US
★★★★★ 5
Our favorite sunscreen
Size: 3 Fl Oz (Pack of 2)
This sunscreen readily soaks in when applying. Smells great and lasts throughout the day.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on April 1, 2026

recommand products