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Description
Holley 550-870K Sniper Stealth 4150 Self-Tuning Fuel Injection System Master KitOverview: The Sniper Stealth 4150 EFI system from Holley features 4, 100LB HR Fuel Injectors capable of supporting up to 650 HP naturally aspirated or 600 HP on forced induction applications. The Sniper Stealth 4150 ECU is capable of fuel map self learning and ignition timing control, improving idle stability, drivability, and wide open throttle horsepower! Did we mention that the Stealth 4150 also includes transmission kick down provisions for GM
Overview:
The Sniper Stealth 4150 EFI system from Holley features 4, 100LB/HR Fuel Injectors capable of supporting up to 650 HP naturally aspirated or 600 HP on forced induction applications. The Sniper Stealth 4150 ECU is capable of fuel map self-learning and ignition timing control, improving idle stability, drivability, and wide-open throttle horsepower! Did we mention that the Stealth 4150 also includes transmission kick down provisions for GM TH350/400, 200R4/700R4 and Ford C4/C6 applications. Part # 34-42 is required for a bolt-in installation.
Features:
- Bolt on 4150 Flange Carburetor Replacement
- Throttle body mounted ECU - no extra boxes to mount
- Supports up to 650hp with Four 100 Lb/Hr Injectors!
- All of the wiring exits below the rear fuel injector cover, for a completely stealth installation.
- Timed spark part for vacuum advanced distributors located under the front fuel bowl, for easy access to the distributor.
- Air entry is machined to fit most stock style air cleaners with air cleaner locator provisions.
- Only 4 Wiring Connections Required! (Battery +, Battery - , Switched Ignition & RPM)
- External fuel pressure regulator required, set to a base pressure of 58.5 PSI, such as 12-886.
- Integrated ignition timing control
- High Resolution Full Color Touchscreen for Initial Setup, Tuning, and Gauge Displays
- Simple Calibration Wizard (answer a few questions about your engine and it creates the base map, then starts tuning on its own!) - NO laptop required!
- Self-tuning ECU means you don't have to be a computer/tuning wiz to have EFI!
- The included Genuine Bosch LSU 4.9 Wideband Oxygen Sensor provides real-time Fuel Map Learn!
- OEM Style TPS/IAC and Fuel Pressure regulator, for years of dependable service.
- Included clamp-on oxygen sensor kit for 2.25" exhaust ensures a leak free oxygen sensor installation, with Stainless Steel T-Bolt clamps and a Stainless Steel (Weldable) oxygen sensor flange
- Available in 3 finishes: Shiny, Black and coming soon, Gold
Application:
| Year | Make | Model | Submodel | Engine Size |
|---|---|---|---|---|
| Universal |
Specs:
| Brand | Holley Sniper EFI |
|---|---|
| CFM | 870 |
| Emission Code | 3 |
| Finish | Shiny |
| Flange Style | 4150 |
| Fuel Pressure | 58.5 PSI |
| Height | 3.28" |
| Injector Size | 100 lb/hr @ 58.5 PSI |
| Inlet / Outlet Size | 3/4-16 Female O-Ring (AN 8) |
| MAP Sensor | 2Bar |
| Max Horsepower Rating | 650 Naturally Aspirated |
| Model | 4150 EFI Conversion Throttle Body |
| Product Type | Sniper Stealth EFI |
| Transmission | 700R4/200R4 |
| Transmission | Ford C4/C6 |
| Transmission | TH350 |
| Warning | California Proposition 65 |
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
4.4 ★★★★★
Based on 8 reviews
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Product Reviews
★★★★★ 5
Focus!
Rather than energy, this gives me focus which is great.
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Reviewed in the United States on April 3, 2026
★★★★★ 5
Energy
Helps with inflammation and gives me more energy.
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Reviewed in the United States on July 9, 2025
★★★★★ 5
Helps with extra energy
I received this as a free sample with my Provite. I purchased another as it does give me extra energy to get through the day.
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Reviewed in the United States on July 8, 2025
★★★★★ 4
3.5 stars. Cant tell if it is this or a variety things I am doing, more details in this review
Sort of a tough one for me to review. Not a clear yes or no. My long answer may help it make sense, and hopefully help you decide to try it (or continue with it if on the fence).
I started using this a month ago. I am just finishing, or just finished my 1st bottle. Prior to that by 2-3 months, I started their Provitalize and Previtalize combo. I initally bought Inerdy as a single bottle, then I had gotten my second bottle as it was part of a bundle, and I was curios. Who doesnt want more energy?
The claims are promising, and it is made to sound like the results will be immediate. I was skeptical because the ingredients in this aren't exactly fast acting as far as I can tell. No caffeine. But it mentioned taking with caffeine to boost effect. Sure, I can do that.
Well no matter if I took it on its own or with caffeine, I cant say I noticed anything significant. But since I had it, I figured I would just keep taking it as the entire supplement formula is pretty good, all stuff our bodies can use anyway, or are downright needful.
I hadnt made any changes other than adding in the 3 products. Maybe I added in other probiotics (because as I learned more about probiotics, the more I realized we REALLY need the for overall health and wellness). I know the probiotics have added great value to my life, but I still wasnt (kinda still not) sure about INERGY.
BUT, in reflection over the past month or so, I HAVE NOTICED, a reduced level of fatigue. For awhile, I was pretty much closing my eyes around 3p for a quicky nap. With the hours before that with a dragged down feel. Like I never fully woke up. Coffee minimally helps, matcha green tea helps a lot, but I still didnt feel overall "good". I'd drink my matcha to power through some basic daily tasks. Didnt really have anything left over for other tasks, projects, fun, etc.
Could be that we're on the cusp of summer, and energy levels naturally rise. Could be that I have begun eating a lot better and greatly reduced my desserts intake (because I dont have that nagging desire for them--def thanks to probiotics!), or it could be a combo of everything, including the ingredients in this INERGY.
That is why I cant say for sure if it is this, or a combo. But I do know I needed time with it, and did not experience anything significant in first couple of uses.
I take this supplement and pretty much all of my probiotics (and prebiotics--do not skip those!) in the morning. I just wake and feel more motivated. I dont necessarily jump right into my day, but the start of my day is easier, less effort. Like I shaved a few years off. That sort of feeling. As I do chores and such, same feeling exists. I have been tackling projects that I have not been able to muster the mental or physical stamina for years. Sad.
Things have been just different for me lately, and I absolutely contribute it to probiotics, prebiotics, and quite possibly this Inergy. As with the probiotics, it very well may take a month, two months, even three months to see/feel the cumulative effect. I think it helps in a more holistic manner.
If you just need a big boost, and not concerned or interested in helping the body to get their in its own time, naturally, I would say B vitamins and matcha. That would produce a more immediate but short lived affect. Could really do both. I still drink my matcha for times I just need to have that added motivation/ambition feel.
So no, this didnt seem to do a thing just by taking it a couple of times. And as I start my second bottle, I am not entirely convinced. But what is in it is good for me anyway, and I can say that the entire package (second time I got it I got it as part of the Previtalize, Provitalize, and Inergy
I will probably continue with it, for awhile anyway. Or however long it seems to be helping me. I did consider stopping it, but at this time I do find value in seeing how much it can help.
I dont rate on price. All their stuff is pricy. As far as probiotics go, good products are pricy. This Inergy? maybe the overall formula could be found for less, not sure.
I'd give this 3.5 stars if I could. 4 makes it sound like sure thing, when I am still not entirely sure. However, I have decided to continue with it (so four stars), and I do think there has been some improvements just not immediate. I think it is worth the try if you are patient. Maybe you will be one of those that notice something right away!
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Reviewed in the United States on June 1, 2025
★★★★★ 5
It works!
I ran out and I could tell a huge difference in the amount of energy I had. I have received my second order and can tell I am back on it. It definitely helps me with energy!!
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Reviewed in the United States on January 22, 2025