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- USA
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- USA
- CAN
Ships within 48 hours · Estimated delivery Jul 7 - Jul 12
For Your Every Summer RSVP, with Code: SUMMER15
Description
Holley HP EFI ECU and Harness Kits 550-604MPFI HP ECU AND HARNESS KIT Looking for a plug and play alternative for your stock or built late model factory EFI engine? How about a replacement ECU for your older Holley C950? Holley has you covered. HP EFI ECU and harness kits are designed to be used with popular factory EFI engines as an alternative to the factory ECU and harness or as a replacement for your C950 ECU. The HP allows you to accurately control the fuel and ignition of your engine
MPFI HP ECU AND HARNESS KIT
Looking for a plug and play alternative for your stock or built late model factory EFI engine? How about a replacement ECU for your older Holley C950? Holley has you covered. HP EFI ECU and harness kits are designed to be used with popular factory EFI engines as an alternative to the factory ECU and harness or as a replacement for your C950 ECU. The HP allows you to accurately control the fuel and ignition of your engine along with additional controls for nitrous, boost or water meth.
Features:
- Optional 5.7” full-color touchscreen LCD allows easy on-the-fly tuning, data-logging or can be used as an easy to see graphical gauge panel
- Eight sequentially driven 8:2 peak and hold injector drivers, capable of driving up to 16 low or high impedance injectors as a standard feature. Multiple staged injector strategies
- Eight channel Distributorless Ignition (DIS)outputs capable of directly driving “Smart” ignition coils or Holley DIS coils. Will drive 2 wire coils with the addition of PN 554-112 high current coil driver module
- Integrated single channel wide band oxygen sensor control. Works with NTK or Bosch sensors
- Internal data-logging standard with a huge 2GB of memory
- 4 Stage progressive nitrous control
- Turbo boost control
- Integrated water/methanol injection control
- Self-tuning fuel table strategy greatly simplifies tuning process
- Individual cylinder fuel and spark control allows you to unlock your engine’s potential
- Works with 4, 6, 8 cylinder engines
- Unique lb/hr based fueling strategy greatly simplifies and commonizes tuning
- Advanced idle, closed loop, and enrichment strategies allow for very stable operation
- ECU is fully potted and can be mounted in the engine compartment or interior
- Sealed automotive and marine grade connectors
- Allows for use of common OEM sensors as well as customer sensor calibration input
- Ignition Plug and Play with GM HEI, Ford TFI, magnetic and hall effect trigger, and other ignition systems. New Plug and Play applications in process. Custom settings can be configured to allow many other applications
- 1-5 Bar MAP sensor capability
- Two channel knock control sensor Inputs for both one or two wire knock sensors
- Dedicated fuel and oil pressure inputs
- Controls both stepper and PWM Idle Air Control (IAC) motors
- Speed density, Alpha-N, or combination fueling strategies
- 4 Programmable high or low Pulse Width Modulated (PWM) outputs and 4 fully configurable inputs can be configured for use
- 4 Stage nitrous oxide control
- Fully featured nitrous control eliminates the need for a separate nitrous controller device
- Can be configured “Wet” or “Dry” with closed loop feedback
- Progressive control based on time, RPM, or boost, requires part # 554-111
- Lean or rich safety cutoff
- Full timing retard/control configurability per stage based on RPM or time
- Integrated Water/Methanol injection control
- Uses Holley Water/Meth solenoids specially designed and calibrated for use with this EFI system to allow the user to enter Water/Meth flow as a percentage of fuel injector flow for Water/Meth tuning precision unmatched in the industry
Application
-
Universal
Specs
| Brand | Holley EFI |
|---|---|
| Emission Code | 3 |
| Ignition Type | Coil - (No Timing Control) |
| Ford TFI | |
| GM HEI Small Cap | |
| Holley Dual Sync Distributor | |
| Injector Connector | Jetronic / Minitimer (Bosch) |
| Product Type | HP EFI Kit |
| Part Number | 550-604 |
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 ★★★★★
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Product Reviews
★★★★★ 5
Very good product
Model: iPad Mini 6/A17 Pro 7th Gen
Nicely attaches to the iPan. Easy and no bubbles. had one and worked it completely out. Had all the need items for the installations. Screen touch works, cover went on without a hitch.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on May 25, 2026
★★★★★ 5
iPad mini screen protector, good price range.
Model: iPad Mini 6/A17 Pro 7th Gen
Good coverage, easy to apply. Thorough dust removal. I have paid much higher price at retail. Good quality.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on May 25, 2026
★★★★★ 5
Very Protective
Model: iPad Mini 6/A17 Pro 7th Gen
Excellent protects the glass from cracking and keeps the iPad clean. Cutouts fit well.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on May 31, 2026
★★★★★ 5
A good product
Model: iPadAir 8/7/6th/iPadPro 6/5th 2026/25/24
This is easy to install and works well
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on May 29, 2026
★★★★★ 4
Good Value Screen Protector That Gets the Job Done
Model: iPad 11th A16 2025/10th
For the price, this screen protector does a pretty good job. The glass feels smooth and responsive, and I didn’t notice any issues using my Apple Pencil after installing it. The screen still looks clear, and fingerprints wipe off easily most of the time.
Installation was easier than I expected, although getting rid of every tiny dust particle was still a little frustrating. I did get a small bubble on one corner, but it mostly disappeared after a day. The protector feels durable enough for everyday use and gives me peace of mind carrying my iPad around.
It’s not a premium brand, but for a budget-friendly 2-pack, I think it’s worth it. Good value overall if you just want reliable screen protection without spending a lot.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on May 7, 2026
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