Shipping Estimate
USA
- USA
- CAN
- USA
- CAN
Ships within 48 hours · Estimated delivery Jul 12 - Jul 17
Promo Codes Available:
For Your Every Summer RSVP, with Code: SUMMER15
Description
Holley EFI 550-869K Sniper EFI Quadrajet Master KitOverview: Are you tired of rebuilding the 50+ year old Rochester Quadrajet (Q Jet) on your classic Chevrolet, GMC, Buick, Oldsmobile, or Pontiac? Introducing Sniper EFI Quadrajet. The first bolt on spread bore electronic fuel injected throttle body system that does not require any additional adapters, sealing plates, or intake manifold swaps! The Sniper EFI Rochester Quadrajet (Q Jet) system retains the same great features as the 4150 Sniper EFI
Overview:
Are you tired of rebuilding the 50+ year old Rochester Quadrajet™ (Q-Jet) on your classic Chevrolet, GMC, Buick, Oldsmobile, or Pontiac? Introducing Sniper EFI Quadrajet™. The first bolt on spread bore electronic fuel injected throttle body system that does not require any additional adapters, sealing plates, or intake manifold swaps! The Sniper EFI Rochester Quadrajet™ (Q-Jet) system retains the same great features as the 4150 Sniper EFI version such as; four 100lb/hr Injectors, built in timing control, a 3.5" full color touchscreen and much more! The throttle body will support up to 500 horsepower naturally aspirated. In addition to all of these great tried and true features, the Sniper EFI Rochester Quadrajet™ (Q-Jet) system will fit most stock air cleaners and offers multiple fuel inlet configurations that allow for a stock appearing installation!
Features:
- Designed to deliver the signature Rochester Roar at Wide Open Throttle!
- Throttle body mounted ECU - no extra boxes to mount
- Supports up to 500hp with Four 100 Lb/Hr Injectors!
- Only 4 Wiring Connections Required! (Battery +, Battery - , Switched Ignition & RPM)
- Integrated ignition timing control
- Transmission provisions on throttle lever for TH350/TH400 and 200R4/700R4
- Fits most stock Rochester Quadrajet (Q-Jet) air cleaners
- Brake Booster adapter included, if required
- Universal Throttle and transmission kickdown bracket included
- 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!
- Complete fuel system includes - 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!
- 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 realtime Fuel Map Learn!
- OEM Style Throttle Position Senser (TPS)/ and Idle Air Control (IAC) for years of dependable service.
- Included clamp-on oxygen sensor kit ensures a leak free oxygen sensor installation, with Stainless Steel T-Bolt clamps and a Stainless Steel (Weldable) oxygen sensor flange
- Patent Pending
Application:
| Year | Make | Model | Submodel | Engine Size |
|---|---|---|---|---|
| Universal |
Specs:
| Brand | Holley Sniper EFI |
|---|---|
| CFM | 715 |
| Coast Guard Approved | Yes |
| Emission Code | 3 |
| Finish | Classic Gold |
| Flange Style | Spreadbore |
| Fuel Pressure | 58.5 PSI |
| Height | 3.28" |
| Injector Size | 100 lb/hr @ 58.5 PSI |
| Inlet / Outlet Size | 9/16-18 Female O-Ring (AN 6) |
| MAP Sensor | 2Bar |
| Max Horsepower Rating | 500 Naturally Aspirated |
| Product Type | Sniper 4BBL TBI Kits |
| Throttle Bore | 1.375 Primary / 2.00 Secondary |
| Transmission | 700R4/200R4 |
| 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
4.7 ★★★★★
Based on 354 reviews
Sort
Product Reviews
★★★★★ 5
Great Place to Start
Format: Paperback
Clear and entertaining
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on February 17, 2026
★★★★★ 5
Engaging Read for Beginners and Techies Alike
Format: Paperback
An engaging and accessible exploration of how computers really work. The author breaks down complex concepts into simple, relatable explanations, making topics like binary, logic gates, and basic circuits far less intimidating. For newcomers, it’s a great way to build a foundational understanding of computer theory with just a touch of electrical engineering.
As someone with a technical background, I still found it entertaining; the examples and analogies added fresh ways to frame ideas I already knew. It’s the kind of book that can bridge the gap between “I use computers” and “I understand what’s happening under the hood.”
Highly recommended for anyone curious about what makes hardware and software tick, whether you’re starting from scratch or just want a new perspective.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on August 19, 2025
★★★★★ 5
CODE is the book you should get.
Format: Paperback
The best book to enter the field. Grateful that Charles Petzold decided to write it, even happier this was one of the first books I picked up.
Recommend to everyone wanting to become a programmer, or just interested in computers.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on January 12, 2026
★★★★★ 5
If you only buy one technical computer book, this is it
Format: Paperback
Disclaimer: I owned the first edition for years and read it a dozen times, mainly for pleasure since it’s not only informative but also just enjoyable to read. I’m a professional software architect and have dozens of textbooks on computer science and engineering so I’ve been around the block.
This is the kind of book I would buy all for all my friends (if I had more than a couple) and family members (if they were even slightly into computers, which they aren’t sadly). Petzold does an exceptional job at describing digital logic and guides you through building a conceptual CPU from very first principles.
I think his bottom up approach is the way to go and has helped me understand complex topics in an extremely simple way. When I’m not reading fiction, this is my go to bedtime reading.
The second edition has about 100 more pages than the first and some content has been completely reworked and it’s great.
If you ever had even a passing interest in knowing how computers work at a very fundamental level, get this book!
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on January 31, 2023
★★★★★ 4
First programmer?
Format: Paperback
As an ardent reader of the past 1st edition, I was fairly excited to get the latest version. That is, until I encountered the history chapter of the new edition.
For one thing, what I do NOT understand in this second edition is the newly added description of August Ada Byron (countless of Lovelace). The author claims it was Babbage who was the first programmer to design the engines, not Ada. I am not trying to start a futile argument here about who has more or fewer contributions, etc.
What I am trying to assert here is that it is undisputed that Ada (unless the new evidence arises) left *the very first demonstration* of what this seemingly imaginary machine, which didn't even physically exist, was capable of through her program. Because Babbage designed the engine itself, that doesn't automatically put him in the position of a programmer (despite Babbage being a brilliant engineer/scientist and may have had a simple or detailed program in his mind). However, it was Ada who gave a definite touch to programming concepts that ultimately led to modern-day programming. Ada deserves more recognition than a mere "tutorial writer," and she is certainly entitled to the title she deserves.
Other than that, like the previous edition, this book is a must-read for people who are from related/unrelated fields. I always loved the 1st edition, and I would do too with the 2nd. Still, I think history should always be approached with more care, particularly if matters have potential controversies.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on January 6, 2023