Shipping Estimate
USA
- USA
- CAN
- USA
- CAN
Ships within 48 hours · Estimated delivery Jul 13 - Jul 18
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
4.1 ★★★★★
Based on 1973 reviews
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Product Reviews
★★★★★ 5
Muy bueno
Color: Brown(17"w)
My husband loved his mini bar; it's excellent quality, each piece arrived in perfect condition, and it was very easy to assemble. Highly recommended if you want to organize and maintain every space in your home with a special touch.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on February 10, 2026
★★★★★ 5
Great Bar Cart for Price
Color: Brown(24.8"w)
This little bar cart is perfect for my space. It holds everything I enjoy using for cocktails and all accoutrements. It took a minute to put it together so make sure you read the instructions. Includes two lockable wheels and wire hanging racks for stemware and bottles.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on April 12, 2026
★★★★★ 5
Great product
Color: Black (17"w)
Love this cart-looks very classy
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on February 27, 2026
★★★★★ 5
Home bar cart
Color: Brown(24.8"w)
My son loves his gift. Fits perfectly in his den, versatile shelves, the perfect size. It’s a Quality bar cart that was easy to assemble and looks beautiful.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on January 24, 2026
★★★★★ 5
Nice small bar cart
Color: Brown(17"w), Color: Brown(17"w)
We have a bar area but it’s downstairs and we are usually upstairs so it’s not convenient. I wanted a little cart to hold a few items but not be in the way. After looking all over the Internet I found this one for a good price. I liked the ability to remove the top so we can bring just that into the kitchen or living room and it looks nice. I had to put it together and it wasn’t too difficult, took about 30 min, HOWEVER I used a ratcheting screwdriver with an Allen wrench attachment or else it would have taken a lot longer! (It does come with the little Allen wrench included so you don’t have to purchase any tools.) All the parts were labeled well and included a couple extra screws. I tightened it up good and it’s sturdy. It doesn’t take up a lot of space. If you just need a small cart this will work!
PS you can opt to leave off the parts that hold the wine glass if you don’t need them/ or want more space on that middle shelf
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on January 23, 2026
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