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Description
Holley HP EFI ECU and Harness Kits 550-602HP ECU AND HARNESS LS1 & LS6 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 & LS6Looking 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 Bosch wideband 02 sensor designed to be used with GM LS1/LS6 engines with factory GM coils and a 24 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" 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
-
Univesal
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 | 550-602 |
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
4.8 ★★★★★
Based on 17 reviews
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Product Reviews
★★★★★ 5
Sooo good!
Color: Rice Probiotics (Barrier Jelly)
This is AMAZING! I used this over my serums and a retinol moisturizer before bed and woke up with the most moisturized and smooth skin I’ve had in forever. It’s a thick consistency but smooths on easily. It is a bit tacky for a little bit before it dries down but absolutely worth it. I learned about this on Beautiful and Bothered and Johnny is right!!
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Reviewed in the United States on March 2, 2026
★★★★★ 4
A little goes a long way
Color: Rice Probiotics (Barrier Jelly)
I love overnight masks, especially for dull winter skin, and this is a really nice one! The texture is extremely thick and jelly like and it has a lovely cooling effect. It didn’t clog my pores or irritate my skin, though I do find that it feels a bit heavy and stifling if applied very liberally. But, after a few tried I’ve finally found the right amount, a little goes a very long way. Because of that, this little pot should last me a long time, even with regular use so it’s a great value! I like to layer it over my barrier protecting/repair products or over retinols and I wake up with hydrated, bright, and fresh skin in the morning! Highly recommend.
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Reviewed in the United States on February 13, 2026
★★★★★ 5
So extremely hydrating
Color: Rice Probiotics (Barrier Jelly)
Best hydrating mask I have ever seen! Used it once so far at night. I would only use at night because it is sticky and stays sticky BUT so worth it! I had applied it 3 hours before going to sleep. During that 3 hours I could see it working. My skin kept getting plumper by the hours. I am 62 years old with deep wrinkles and very dry skin. Guess what...my skin was not dry all day after using this mask overnight. Can not wait to keep using it. My deep wrinkles are plumped up. I have bouncy skin.
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Reviewed in the United States on May 1, 2026
★★★★★ 5
Great, way better than "slugging"!
Color: Rice Probiotics (Barrier Jelly)
It's heavy, but less so than Vaseline. Vaseline causes me to breakout even though I'm constantly told it shouldn't. This feels sticky, but otherwise calming and seems to help my skin heal. I have pcos - large pores and produce extra oil, rosacea, and just very sensitive skin. You definitely have to let it sit before laying down but my skin is always less irritated in the morning.
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Reviewed in the United States on January 7, 2026
★★★★★ 3
It's just okay
Color: Rice Probiotics (Barrier Jelly)
Meh. I feel like it just stayed on top of my skin and didn't really help. Not bad, but nothing special.
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Reviewed in the United States on May 28, 2026