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Description
Holley 550-871 Holley Sniper EFI Stealth 4150 Kit - Black FinishOverview: 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. For a complete installation, Master Kits include a complete fuel system with an external fuel pressure regulator preset to 58.5psi, 20ft of 3/8" Vapor Guard Fuel Hose, Fuel Pump, Filters, necessary hardware, and bulkhead fitting to return fuel into the tank!
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, 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 | Black |
| 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
4.2 ★★★★★
Based on 603 reviews
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Product Reviews
★★★★★ 4
Smell
Size: Queen (2 Count), Color: Original White (Cooling)
The fact that there are not more comments on the smell of these pillows has me worried about some of yall. Listen, I LOVE the weight, and the firmness, it’s perfect for that. However, these pillows are RANK. They have a very strong mildew-ish smell that lingers. I took the outer cover off and washed it and let the pillow air out for a few days, the smell is still very strong when you press your face against it, which one does because it is in fact designed for that purpose. It smells so bad. It’s nauseating. I can smell it through two pillowcases and blanket that I threw on top of them hoping an extra layer would trap the smell. I’ll bake them in the Texas sun tomorrow and hope that helps, because otherwise these are the perfect pillows for someone who wants to feel like they are hugging a torso but can’t stand the sound/feel of someone else breathing. I don’t know…4 stars, if the smell goes away I’ll come back.
Update: many many days later. Either they don’t really smell anymore or I got use to it. They’ve held their firmness and shape well. I like them.
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Reviewed in the United States on March 9, 2026
★★★★★ 5
Actually Cooling Pillow
Size: Queen (1 Count), Color: Original White (Cooling)
This is a really nice pillow, I was worried it would be too soft or too firm but it's just right and it's actually cooling, it feels cool every time I touch it. I've noticed an improvement in sleep since using it. Would recommend!
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Reviewed in the United States on May 27, 2026
★★★★★ 5
Repurchased in King Size – Still Love These Cooling Pillows
Size: King (2 Count), Color: Original White (Cooling), Size: King (2 Count), Color: Original White (Cooling)
After using the queen-size version of these pillows for over a year, we purchased the king-size set when we upgraded to a king mattress. Both my husband and I really like them.
The cooling feature works well, and we like that each side feels different—when I run cold, I use the softer bamboo side, while my husband prefers the cooler side since he tends to sleep hot. They fit well in our king-size pillowcases and feel supportive in all sleeping positions, whether I’m on my stomach, side, or back.
I also appreciate that you can remove some of the filling to adjust the firmness. The covers are washable, which makes them easy to maintain. Overall, we’re very happy with this repurchase and the long-lasting comfort.
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Reviewed in the United States on April 15, 2026
★★★★★ 3
Not great at cooling
Size: Queen (2 Count), Color: Original White (Cooling)
Each pillow cover has 2 sides, one marked for cooling, and the other a different fabric. The cooling side is about the same effectiveness as having a silk or satin pillow cover. It's only cool when you first touch it. The cooling side doesn't seem to absorb or wick moisture, so if you are sweaty - it keeps the moisture in place. You'll definitely want a regular pillow case over the pillow cover. In fact, if you suffer from night sweats, the non-cooling side is actually more comfortable. The pillow fill is ample, and simple to squish around for more support for your neck, etc. Think bean bag. But it will retain your impression after use. I find I need to do as I did when I had down pillows - give it a few good shakes in the morning when I make the bed to get it evened out for the coming night. In all, it is a well-made and comfortable pillow to sleep on, but it does not excel in cooling.
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Reviewed in the United States on May 29, 2026
★★★★★ 5
excellent pillows i bought two sets!!
Size: Firm Queen (2 Count), Color: Original White (Cooling)
I ordered these for my son who has neck issues and has gone through so many pillows trying to find one that he liked. They’re heavy, so i was worried that they might be “too” heavy to be able to sleep on comfortably, so I ordered a second set, one firmer than the other (just in case) and gave him a set for Xmas and he loved the first set so much without even trying the less firm ones.He also needs the cooling factor and these offered that, too. They are filled with pieces of memory foam (tons of it) and each pillow can be modified by removing some of the foam. The covers are beautiful, high quality fabric with a zipper so ts easy to remove or replace the foam pieces. The size is perfect and they keep their shape. I kept the second set i ordered rather than returning them and i love the pillows. I actually modified two by removing some of the foam pieces. I kept the foam pieces in a zippered pillow protector and i can always adjust mine when or if i need to.
1000% love these.
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Reviewed in the United States on March 22, 2026