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Description
Holley 550-871K Holley Sniper EFI Stealth 4150 Master 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. 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 | 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
4.9 ★★★★★
Based on 17 reviews
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Product Reviews
★★★★★ 5
Border Collie Approved: Easy to Clean, Durable, and Great Bounce
Size: Medium (2.5"), Style: Fetch Pack 2
These are the best balls out there for dogs. These fit great in the chuck-it ball launcher, which we need to wear out my border collie. They fit her mouth properly and, most importantly, do not absorb all the spit or water after a good rain. They are quick to clean off and have good weight so you can let them fly! Furthermore, they bounce well, which is perfect for my dog that likes to catch them on a bounce. The ball is a strong rubber, so should not be easy to chew up. I've used these for years, and the only time I've had to replace them is when one gets lost in the hay field. I highly suggest these as replacements for the common tennis balls.
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Reviewed in the United States on July 19, 2025
★★★★★ 4
Heavy duty.
Size: Medium (2.5"), Style: Fetch Pack 2
My dog was not interested, but it’s a good product
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Reviewed in the United States on April 11, 2026
★★★★★ 5
Treats and plenty of ball throwing with these doggie toy
Size: Medium (2.5"), Style: Fetch Pack 1
I have actually purchased these twice already. I love the one that glows in the dark but it still got lost in my yard lol. My dog is a big breed half pitt/Labrador so she did chew through one of them already. I play ball with her every single day but I DO have to take them away from her because she will destroy them. They are great to add in treats as well, that was one of the my favorite things about them as well. They do last just if you have an over zealous chewer do not let them keep them for long periods of time. They are a good value for the price. Buy them your dog will love it!
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Reviewed in the United States on August 2, 2025
★★★★★ 5
My Female GSD loves
Size: Medium (2.5"), Style: Fetch Pack 1, Size: Medium (2.5"), Style: Fetch Pack 1
Shasta is my smallest. Six in December (2025) along with her brother. She’s 100 lbs and outside, completely ball driven see last picture. Don’t let the size (2.5”) of these Chuck-It balls deter you. If your larger Breed dog has any orthopedic issues, has already torn their ACL etc, one has arthritis but wants to play. This size is perfect!
Shazzy was born with several ortho issues. I don’t throw balls distance but right to her. This size and lighter weight assure even when Shazzy is spazzy w excitement, she’ll catch the ball mid air.
The green balls are softer, and glow in the dark. In summer we can play well past dusk and I can see them!
Her personality shows in the pictures. Playing ball is part of her. These balls are just perfect for her situation. Somehow they disappear, she loves making baskets, puts them in my tractor bucket, or my gardening bucket..then get put in burn pile, trash etc. I keep replacing them because she’d look day and night if we actually ran out!! 🙏✝️👍🏼👍🏼
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Reviewed in the United States on September 3, 2025
★★★★★ 5
Durable and fun
Size: Medium, Style: Ultra Tug, Size: Medium, Style: Ultra Tug
This is a cool toy. My dog took to it right away. It tosses great. I like that you can play a little tugging along with fetch. We mainly use it outdoors. It feels very strong and durable. For size reference my dog is a mini golden doodle and weighs about 30lbs.
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Reviewed in the United States on February 22, 2026