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Description
HP EFI Universal MPI Retrofit Kits - 550-500Overview: 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 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
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 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 |
| Ignition Type | CD Ignition (No Timing Control) |
| Injector Connector | Jetronic / Minitimer (Bosch) |
| Product Type | Universal Multi Port |
| Terminator LS Options | Fuel, Spark |
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
4.2 ★★★★★
Based on 5 reviews
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Product Reviews
★★★★★ 5
This mattress cover is great! Well worth your money
Size: Twin XL, Style: 1 Green
This mattress cover is so comfortable. I am scheduled for back surgery in a week so when I find something I can sleep on and call it comfortable you best believe it is! It fits well, it’s pretty and it’s very fluffy. Seems to be made very well. I am confident that I’ll get a lot of wear out of it.
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Reviewed in the United States on May 29, 2026
★★★★★ 5
Very Comfortable - Love this!
Size: Full, Style: 1 Green
So far, so good! I am going on my first night trying this mattress topper out. It feels very comfortable and definitely is fluffy, but not too fluffy. I did not "fluff it out" or put it in the dryer to fluff it out quicker, so perhaps it still needs some time to fluff out some more. It was very easy to place on my mattress. I didn't have to fight with it as I normally would when fitting a sheet to my mattress. I love that it stretches over the sides of the mattress to hold it in place. The bamboo truly gives a cooler effect, which will be very helpful in the summer time. I used a microfiber mattress topper prior to ordering this topper. So far, the comparison is that this one appears to be well made and durable, unlike the microfiber one I had before that changes color as it gets old and dirty and is impossible to clean. The old one actually ripped and would constantly move. I am excited to see how well this one holds up over time. I had no trouble placing a fitted sheet over this mattress topper. I love that this one is machine washable and is able to be placed in the drier. It feels very nice on my legs and is comfortable for my back as well. The padding doesn't feel thick or bulky but definitely adds a softness that is super comfortable. It's too soon to tell if it's water resistant as I haven't tested that feature out yet. I placed it over an old, springy mattress and it truly feels like I have a whole new mattress. Time will tell how well this product does the job and I will update this review if I end up having any issues with it.
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Reviewed in the United States on May 25, 2026
★★★★★ 5
OMGAAAAAWD!!! HEAVEN!
Size: Full, Style: 1 Green, Size: Full, Style: 1 Green
All I can say is OMGAWD!!! Thank You~!~!! We got a new mattress after the previous "The Cloud" Serta pillow top (I'll never have another one) lasted for less than 8 years and I totally despised not being able to flip it models failed.. The new model is also a hybrid mattress, but is flippable and was just a bit too firm. I was feeling progressively more and more uncomfortable as the nights wore on, and with my serious back problems.. this just wouldn't do.. So I began searching "Our Beloved Amazon - heh" for an alternative, and after quite some time and research finally landed on this wonderful topper. It's like sleeping on top of well stuffed Ida Down on top of piles of silk. So very comfortable and my back pain is virtually completely gone now -such a relief! Be sure you follow the instructions on care and initial setup. You Do have to let it fluff out because of the vacuum packing (it wasn't really heavy btw). Mine decompacted fine, but I still want to run it through the dryer when we next venture to the laundromat. Shake it a little here and there when you take it out and at least let it sit for a few hours. It was just as easy to put on the bed as a regular mattress protector, and I also put my regular protector on top of it for added security and waterproofing. The materials feel like they are of good quality.. Viscose is also called Rayon and can be made from a number of different materials, so take good care of it and follow the washing instructions carefully. Delicate only, and cool only, and use only a horizontal washer that does not have a central agitator or you will tear it up. Only dry on low temperatures (preferably in a very larger laundromat dryer so it has plenty of room to loosely toss about. Drying it in the sun is alright as well, but it won't fluff like you want it to. I recommend using a waterproof and bug proof protector on top of this just to be sure you take care of it properly.
Now I want to buy one for both my Mother and my Aunt HAHAHHA! TG it is in my price range.. barely.
(Addendum: I have run it through the big dryer at the laundromat.. The dryer was cold so I gave it a quick warm on medium for anout 2 minutes and then tumbled on low for quite some time. The topper was fully ready in about 25 minutes, but I decided to elt it go on low while I did the rest of my laundry. It did perfectly and is just like the manufacturer photos.. I was so tired when I arrived home that I just flaked out on top of everything.. It was so comfortable that I was out liek a light in very short order and slept beautifully. I can attest that if you use this below your sheets instead of covering it with an additional mattress protector, that it does have better cooling effect. I will of course keep my waterproof/bugproof protector on top just for safety. The cat is nutz about the new topper as well.)
Namaste.
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Reviewed in the United States on August 6, 2025
★★★★★ 4
Not like the pictures but well worth the money
Size: Queen, Style: 1 Green
4 stars because it is not nearly as padded as the descriptions and images make it seem. The filling flattens easily and doesn’t provide any support.
That being said it does make my bed more comfortable and soft and has improved my sleep quality. I have a 12 in soft/medium firm memory foam mattress that was wonderful for the last +2 years till my back surgery ~6 months ago. Since then my joints ached when trying to sleep and when waking, my back would be all out of place and achey, and I was untested. Since buying this topper these issues have improved by 80% or more. It is a great addition to my bed and I don’t regret buying it.
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Reviewed in the United States on May 18, 2026
★★★★★ 5
Pleasantly surprised!
Size: Queen, Style: 2 Dark Gray
I had been searching for a quality mattress topper in hopes of extending the life of our mattress. I compared a few options and kept coming back to this one. I have to admit I was skeptical because the price point was lower than many options. This topper is SO comfortable and soft! I left it laying out for a couple hours and then followed the instructions to put it in the dryer. Worked like a charm. I’ve been going through issues with hip pain and this has made a difference in my sleep and I’m waking up in less pain. So happy I tried this out. The padding is so comfortable and fit on the mattress using the same sheet we had.
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Reviewed in the United States on May 17, 2026