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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
4.0 ★★★★★
Based on 206 reviews
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Product Reviews
★★★★★ 5
It did work
Size: 1-Pack (32 oz)
Sealed a small nail hole in a front tractor tire. Better than taking to shop for inside patch or making the 3x bigger for a rope patch.
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Reviewed in the United States on May 6, 2026
★★★★★ 5
Fixed a Bead Sealing Issue
Size: 1-Gallon (128 oz)
For traction in snow, I recently installed new "agricultural" style lugged front tires on a Simplicity garden tractor from around 1980. The tractor looks like it's survived a war, evidently having had a hard life as a workhorse owned by a school district.
The front rims are rusty, and I naively thought the beads of these thick tires would seal properly anyway. They didn't.
The jug of sealant ships with a valve core removal tool. Removing and reinstalling the cores is a piece of cake if you've never done it. I pumped a generous amount of the product into each tire and then did a few fast laps in a grassy paddock. It's a Kohler 19HP twin and it's a bit of a rocket. 😎 One tire sealed, the other didn't, and there was still a faint hiss. I added more product to that side and repeated the process. It seemed to hold. The next day that side was flat again, so I added more sealant and this time it held.
Based on this experience, I'd say that instead of strictly following what the instructions recommended as an amount per tire, keep adding product in increments until the tire holds air.
It's good stuff and it works. Will the tire self-heal if I puncture it? I don't know yet. It saved me the headache of having to remount these small tires or install tubes.
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Reviewed in the United States on May 24, 2026
★★★★★ 5
Stop wasting your money on green slime or Fix-A-Flat or any of the other tire sealant
Size: 1-Gallon (128 oz)
Flat out is by far the best product on the market to fix flat tires and prevent flat tires. This will be the second gallon jug that I purchased that stuff on everything. all of my landscape equipment has it in every tire. And to paint and even better picture for you I have a scag mower that is 20 years old The tires are probably 18 years old ugly as could be and would not hold air until I put the flat out in it it has been sitting now for over a year and every tire still has air That's how good the stuff is. Don't just buy one gallon by two cuz it will get used
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Reviewed in the United States on July 11, 2025
★★★★★ 5
John Deere 5x4 (gator)
Size: 4-Pack (128 oz), Size: 4-Pack (128 oz)
Excellent product. The John Deere 5x4 (Gator) in picture sat for ten years, the tires were flat, the front tire was the worse. To move this Gator from my neighbors place he had to load it on a trailer, he aired up the rear 4 tires but the front would air up and leak before he could move it. He put a make do wheel to get it moved to my place. shortly after unloading the rear 4 tires went flat. All were badly weathered. I read about a stop leak "FLATOUT" I ordered one bottle and put it in the front wheel and I aired it up, it held air for several hours. I called FLATOUT Support and told them I put 1/2 bottle in front tire and how it helped, He said it calls for a full bottle per tire so I added the rest of the FLATOUT. I bought four more bottles of FLATOUT and put those in all 4 tires, put air in and drove the unit a block. next day two tires were low so I finished putting FLATOUT in and aired the tires and drove two to three blocks. the weather snowed so I parked the Gator for two weeks, the tires never went flat. I checked the air pressure and had lost about 2-3 pounds, refilled with air and on a warm day drove the Gator about 2 miles. No flat tires. Note the front tire had a weathered crack 4 inches long where it sat folded for so many years and I saw where this product had sealed this leak and no air loss after two weeks of sitting.
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Reviewed in the United States on April 7, 2021
★★★★★ 5
Recommended
Works extremely well for tire patch repairs. Just be sure product is totally dry before applying patch on inner tube or interior of tubeless tire.
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Reviewed in the United States on January 25, 2026