SKU: 47724201336

HP EFI Universal MPI Retrofit Kits - 550-501

Sale price$2249.97 Regular price$2499.97
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Ships within 48 hours · Estimated delivery Sep 21 - Sep 26

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Description

HP EFI Universal MPI Retrofit Kits - 550-501Overview: Do you have a Mopar, Ford or other type engine you want to install multi port fuel injection on? No, problem, the Holley HP universal MPI retrofit EFI kits are designed to be used with any V 8 intake manifold. The kit comes with injector bungs and un machined fuel rails so you can modify to fit any single plane 4bbl intake manifold. The HP universal retrofit kits also come with the necessary wiring, ECU, sensors and throttle body. Just

Overview:

Do you have a Mopar, Ford or other type engine you want to install multi-port fuel injection on? No, problem, the Holley HP universal MPI retrofit EFI kits are designed to be used with any V-8 intake manifold. The kit comes with injector bungs and un-machined fuel rails so you can modify to fit any single plane 4bbl intake manifold. The HP universal retrofit kits also come with the necessary wiring, ECU, sensors and throttle body. Just select the fuel pump and injectors of choice and you are off and running.

Features:

  • NEW V2 SOFTWARE FEATURES
  • “Quick Start” ignition and fueling strategy for LS x Engines
  • Data Logger. Scalable axes, Smoothing, Multiple graph view ability, Pre-defined notes fields and many more
  • Strip Chart Real-Time Data Viewer
  • Integrated Boost Control - Boost vs Time, Boost vs Gear (Time or RPM), Boost vs RPM, Boost vs Speed, Launch control. Boost launch builder, Over-boost safeties, Boost scramble
  • Traction Control - Power reduction via timing, nitrous percentage or boost (Requires Davis Technologies Holley Module)
  • “Quick Start” fueling for all engines
  • Option for VE based fueling strategy
  • Fuel Map and Learn Function Smoothing
  • Configurable User Password Protection
  • Fully Configurable lap top Gauge Panel
  • 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
  • Plug and Play control of factory GM 24x and 58x LSx engines
  • 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 24x and 58x LSx engines, 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 tu

Application:

Year Make Model Submodel Engine Size
Universal

Specs:

Brand Holley EFI
Emission Code 3
Product Type Universal Multi Port
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: 47724201336

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Reviewed in the United States on May 18, 2026
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Jennifer Kuhns
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I've only had these pillows for about a week. They are a great quality pillow. The cover is soft and seems well made. My only complaint is that they are VERY full pillows. If you're tall with broader shoulders, you'll probably love them. If you're shorter with a smaller frame you will probably feel like your head is too high and your neck at a weird angle (my problem). There seemed to be mixed reviews about softness....I would consider these a nice medium pillow. Soft filling but firm enough that your head doesn't sink to the bed. Definitely NOT a down-like pillow, so if that's what you're looking for, this is not for you.
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Reviewed in the United States on April 10, 2026
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Maria Fernanda Rojas Mejia
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★★★★★ 5
Soft, fluffy and surprisingly comfortable
Color: White, Size: Queen (Pack of 2), Color: White, Size: Queen (Pack of 2)
I really liked these pillows. I tried to show different things in my photos because I wanted people to see the details: the design, how fluffy they are, and how full and thick they actually look. They are so full that the pillowcase even looks tight once you put it on, which I actually loved because they look luxurious and well-filled. At first glance they look very thick and high, but once you lay down they feel soft and fluffy instead of hard. They adjust comfortably and feel very cozy whether you’re sleeping, relaxing, or even reading before bed. I think they offer a really good balance because they feel supportive without being stiff. Of course, pillow preference is very personal—some people like lower pillows and others like higher ones—but for someone who likes fuller pillows that are still soft and comfortable, these are great. They are spacious, cozy, and feel like a very good purchase overall. I honestly don’t have any complaints so far. Definitely happy with them.
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Reviewed in the United States on May 15, 2026
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RF
Bozeman, US
★★★★★ 5
Great quality pillows. Very difficult wrapping.
Color: White, Size: King (Pack of 2)
The Pillows are the real deal. Very fluffy but with good support. I was surprised by the weight of the box they came in, pretty heavy so you know there’s good quality pillows inside. The one negative is that the pillows are packed in very very tight plastic because they come compressed. But the thing is, it’s really a chore to open them. You have to be careful not to cut through the plastic to the material, but the plastic is put on so incredibly tight that it’s even hard to get your finger underneath. But I found a way to open them. Near the top, insert A very flat metal ruler as far in as you could get it. Then cut through the plastic that’s above the metal ruler. That prevents a sharp tool from damaging the pillows. As you get through the plastic above the ruler, keep pushing the ruler further down into the package. Believe me, this simplifies what could be a very difficult unpacking. I am very surprised that the company that makes them does not insert the type of opener that you find on boxes you receive in the mail or even packages that you get from the grocery store where you just pull a tab and that opens the package. These are really good pillows, but you must be very careful about using a sharp object when opening the box and when trying to cut through the plastic. I am a strong man and have the tools needed, a very flat metal ruler, and a box cutter, knife, or razor. Good luck. !!
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