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Holley Sniper EFI Self-Tuning Kit - Shiny

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Holley Sniper EFI

Holley Sniper EFI Self-Tuning Kit - Shiny

Now available on summitracing.com - SNE-550-510

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Part # 550-510

40 Reviews

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Emissions

This part is legal for sale and use on Uncontrolled (Non-Emissions Controlled) Vehicles.

See Emissions Details

Holley's Sniper EFI is the absolute best way to upgrade your car to fuel injection with just 4 simple connections required. This 4-barrel system features a dual pattern bolt on design built to fit 4150 flange & spreadbore manifolds. Sniper is designed to be installed at home in your garage or driveway with limited tools and the support of Holley's comprehensive installation manual and videos. An afternoon in the garage and you will be enjoying improved engine performance, better MPG's and easier starting. Featuring a throttle body mounted ECU with no extra boxes to mount. Not exactly sure if you're going forced induction and/or naturally aspirated yet? No worries! This kit supports up to 650hp naturally aspirated and 575hp boosted with four 100 Lb/Hr injectors. After the simple installation it's time to let your Sniper begin the self-tuning process. Our user-friendly calibration wizard allows you to just answer a few questions about your engine and the system will begin self-tuning with no laptop required. You don't have to be a computer wiz or specialize in tuning to use a Sniper EFI system! Use the high resolution 3.5" full color touchscreen for tuning and gauge displays. Sniper EFI is part of a complete ecosystem! Your new Sniper kit pair's seamlessly together with Holley's Sniper Hyperspark Ignition, Fuel System's, Air Cleaners, Throttle Body & Digital Dash to unlock the full potential of your build. Complete your fuel injection journey by checking out our full offer of ignition, fueling and accessories!

Features:

Dual Pattern bolt on carburetor replacement, designed to fit 4150 Flange & Spread Bore manifolds - (Spread Bore Sealing Plate Part #9006 is recommended)
Self-tuning ECU means you don't have to be a computer/tuning wiz to have EFI!
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!
Only 4 Wiring Connections Required! (Battery +, Battery - , Switched Ignition & RPM)
Throttle body mounted ECU – no extra boxes to mount
High Resolution Full Color Touchscreen for Initial Setup, Tuning, and Gauge Displays.
Supports up to 650hp with Four 100 Lb/Hr Injectors!
Internal fuel pressure regulator eliminates the hassle of plumbing an external fuel pressure regulator (Preset to 58.5 PSI)
Integrated ignition timing control & coil driver
Available in base & master kits (Master kits include complete fuel system consisting of; 20ft of 3/8" Vapor Guard Fuel Hose, 12-920 Fuel Pump, Filters, necessary hardware and bulkhead fitting to return fuel into the tank!)
The included Genuine Bosch LSU 4.9 Wideband Oxygen Sensor provides realtime Fuel Map Learn!
OEM Style TPS/IAC and Fuel Pressure regulator, 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
Certified to ISO 8846, SAE J1171 & United States Coast Guard Requirements for Ignition Protection & Fire Resistance. Making Sniper EFI the perfect choice for carburetor to marine fuel injection conversions!
A Flame Arrestor is REQUIRED for marine installations, such as part number, 720-1 or 720-13
Patent Pending

Bangshift.com: The Caddy Powered C10 Gets A Holley Sniper EFI

RacingJunk.com: Installing Holley's Sniper EFI System

FullSizeBronco.com: Holley Sniper EFI Install

HOT ROD Tests Holley’s Sniper EFI

Motor Life: Sniper Installation Guide

United States Coast Guard Approved
Certified to ISO 8846, SAE J1171 Requirements

Brand	Holley Sniper EFI
CFM	800
Coast Guard Approved	Yes
Emission Code	3
Finish	Shiny
Flange Style	4150
	Dual Bolt Pattern
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	650 Naturally Aspirated
Model	4150 EFI Conversion Throttle Body
Product Type	Sniper EFI 4150
Transmission	700R4/200R4
	TH350
UPC	090127728994
Part Number	550-510

Holley EFI CAN to USB Dongle Communication Cable
Compatible w/ Holley EFI, Sniper EFI, and Terminator X Software
Part# 558-443
$71.70
Qty:
Holley EFI Oxygen Sensor
Replacement Sniper and Terminator X O2 Sensor
Part# 554-155
$143.95
Qty:
Earl's Fuel Pressure Gauge Adapter
Earls - 1/8" NPT in Hex -6AN Male to -6AN Female
Part# AT100199ERL
$19.61
Qty:
Earl's -6 AN Male to 9/16"-18 (AN6) O-ring Port
Earls -6 AN Male to 9/16"-18 (AN6) O-ring Port
Part# AT985006ERL
$11.33
Qty:
Earl's Pressure Gauge
Oil-Filled - 0-100 PSI - 1/8" NPT Male Thread
Part# 100187ERL
$46.52
Qty:
Holley EFI Replacement Regulator Kit
Replacement Regulator Kit for EFI Regulators and Sniper EFI throttle bodies.
Part# 12-878
$25.82
Qty:
Idle Air Control Motor
Replacement Idle Air Control (IAC) Motor for Sniper EFI TBI Systems, Sniper 90/92/102mm Throttle Bodies, Terminator TBI, Avenger 4bbl TBI, HP 4bbl TBI, Commander 950 & Digital Pro-Jection Systems
Part# 543-105
$77.85
Qty:
Sniper EFI Coolant Temperature Sensor:
Service Replacement Coolant Temperature Sensor
Part# 543-120
$30.70
Qty:
Throttle Position Sensor
Replacement TPS for Terminator and Sniper EFI Throttle Bodies as well as a variety of other Holley EFI Throttle Bodies.
Part# 543-111
$71.70
Qty:
Sniper EFI to Holley EFI Dual Sync Distributor Adapter Harness
SNIPER EFI TO HOLLEY DUAL SYNC HARNESS
Part# 558-493
$40.95
Qty:
Sniper EFI 3.5" Handheld Controller
SNIPER EFI 3.5 TOUCH SCREEN LCD
Part# 553-115
$348.95
Qty:
Sniper EFI Installation Kit
Sniper EFI Installation Kit
Part# 520-1
$41.35
Qty:
Earl's AN Port Plug - Hex Head
-6 AN Port Plug w/ O-Ring Seal, Black Anodized Aluminum - 2 pieces
Part# AT581406ERL
$8.23
Qty:
Sniper EFI Input/Output Harness
Input/Output Harness for Sniper EFI Systems
Part# 558-491
$56.32
Qty:
Sniper EFI Coil Driver Module
COIL DRIVER MODULE
Part# 556-150
$143.95
Qty:
Sniper TBI Main Harness
Main Battery Harness with Fuse and Fuel Pump Relay
Part# 558-490
$143.95
Qty:
Hooker BlackHeart Oxygen Sensor O2 Bung 3.0" Clamp-On Style
Oxygen Sensor O2 Bung 3" Clamp-On Style for all vehicles that utilize an Oxygen sensor
Part# 71014301-RHKR
$43.00
Qty:
Hooker BlackHeart Oxygen Sensor O2 Bung 2.5" Clamp-On Style
Hooker Blackheart Oxygen Sensor O2 Bung 2.5" Clamp-On style
Part# 71014302-RHKR
$43.00
Qty:
Hooker BlackHeart Oxygen Sensor O2 Bung 2.25" Clamp-On Style
Hooker Blackheart Oxygen Sensor O2 Bung 2.25" Clamp-On style
Part# 71014303-RHKR
$43.00
Qty:

This part is legal for sale and use on Uncontrolled (Non-Emissions Controlled) Vehicles.

The following vehicles are considered Uncontrolled (Non-Emissions Controlled) Vehicles:

1965 and older U.S. manufactured California Certified vehicles
1967 and older U.S. manufactured Federally Certified vehicles
1967 and older Foreign manufactured vehicle

WARNING: It is against the law to install this part on an Emissions Controlled Vehicle

The following vehicles are considered Emissions Controlled Vehicles:

1966 and newer U.S. manufactured California Certified vehicles
1968 and newer U.S. manufactured Federally Certified vehicles
1968 and newer Foreign manufactured vehicle

Quickstart Guide
Quickstart Guide for Part# 550-510

Instructions for Part# 550-510
Instructions for Part# 550-510

Holley EFI Dealers
Do you need a custom kit built for your application? Do you need a system installed and tuned? Click here to find the Holley EFI dealer in your area!

Sniper EFI SD Card Contents
Sniper EFI SD Card Contents

Wiring Instructions for Part# 550-510

Troubleshooting Guide for Part# 550-510

Quickstart Guide for Part# 550-510

Have a question about this product?

Question
I was wondering if the holley efi sniper would support a draw through blower like what I have. I have a magnacharger 122, (carb sits ontop), and I''m wondering if the sniper would suffice on my setup. Need to know if I can go with a sniper or if I would have to get a super sniper. The blower should run on single digit boost.
By Derrick H. on October 16, 2019
Answer
A standard Sniper EFI throttle body does not have the boost reference port provisions. The Super Sniper throttle body comes machined for the draw-through style boost reference port. The 550-518 Super Sniper is what we recommend for your application.
Helpful?
Question
Can I run the Holley regulator/filter P/N 12-876 with this sniper system? I see this sniper system has a built-in regulator and wasn't sure if having a second one in-line will cause an issue.
By Darin A. on November 25, 2019
Answer
If you plan on running an external regulator, it is recommended to remove the regulator in the sniper EFI main body.
Helpful?
Question
Wondering about the detail of the fuel graph the system uses. Is it 8x8, 16x16, smaller or larger? Is it adjustable via laptop such that I could set the high vacuum values to not as high and pickup clarity on my motor that makes little vacuum? Can I use a laptop and do extensive tuning or is the handheld it?
By Andrew P. on January 9, 2020
Answer
https://documents.holley.com/techlibrary_sniper1.2.17installer.zip The software is free to download. Most of the fuel tables are 31x31. Yes, it is nearly infinitely software adjustable for various engine combinations. The initial setup is done with the handheld, if you need to fine-tuning adjustments, the software is normally the best solution.
Helpful?
Question
What is the lowest I could set engine idle RPM?
By Kyle T. on November 15, 2019
Answer
In theory, a sniper unit could function below 100rpm. The engine itself would be the determining factor for that.
Helpful?
Question
Will this work with a Ford AOD transmission? If so, what else do I need? Brackets? etc...
By Sean S. on March 1, 2020
Answer
This product does not have a C4 kickdown, Lokar has a cable kit for this application. The Sniper Stealth 4150 has the C4 kickdown however. Check out part number 550-870
Helpful?

Reviews

4.8 out of 5 stars

5 star
83%
4 star
18%
3 star
0%
2 star
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1 star
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Your Review

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Straightforward and complete

By Jeffrey B on February 13, 2018 | Verified Owner

Kit was an easy install under the hood. Instructions are clear on many points with helpful illustrations and pictures to walk through installation and initial set up and start. My only complaints are that it was difficult to find information on mating components and fittings and found a lot of helpful information online and on the Holley Snifer Owners Facebook page, and that the manuals included with the kit did not contain all of the information of the online manuals and troubleshooting charts could only be found online. I am very happy with the system so far. By pairing with the fuel tank kit it made for a clean and simple overhaul of the system.

Great for the cold starts!

By Mike Z on February 13, 2018 | Verified Owner

Wakes my 383 stroker up on the cold days! This unit is amazing! The black finish is great!

Super Excited about this project.

By Bob S on February 13, 2018 | Verified Owner

I am super excited to get this project rolling. I have not completed the install yet, but am highly impressed with the Sniper EFI, the detailed documentation provided and the support team that has been ready and willing to answer any of my questions as I prepare. Thank you! Update - I have had this on my car for a couple of years now. It is probably the most significant upgrade I have done to my 68 Camaro. I absolutely love it.

Sniper Efi++++++

By Joshua F on February 13, 2018 | Verified Owner

I would recommend this to anyone looking to switch from a carb or an old efi system. Easy to install and easy to read and follow instructions.

Jon Mitchell

By Jon M on February 13, 2018

Absolutely love it night and day difference, such easy installation and no troubles turned it on and drove haven’t adjusted anything. Highly recommend, just wish I could find a holley efi sticker to go up my a pillar. Thanks Holley!

Dave

By David S on February 14, 2018 | Verified Owner

After years on the fence, I decided to bite the bullet and after reading PRO'S and CON'S decided on the Sniper EFI, able to handle my HP demands and appearance I was sold,also went with the tank a pump. Easy installation and as promoted easy tune! Can't be happier! Great Product!

Easy to use and great directions

By Kareem S on February 14, 2018 | Verified Owner

There are many great products on the market that users have difficulty with due to bad or incomplete directions and support information. Holley really knocked it out of the park with a great product and great support for the average user.

Perfect Solution!

By James M on February 15, 2018

In the middle of the conversion from an Edelbrock and so far the kit has been a simple swap out. Super high quality, very detailed instructions with photos. Can't wait to finish up and get it dailed in!

Finishing Touch

By Tom B on February 15, 2018 | Verified Owner

Installed on the newly built 460 in my 1978 F150. Corrected all the timing and performance issues I was having with the setup. Also got the in-tank fuel pump setup which made for an extremely clean installation. Looks and runs great.

Great results on a Ford 302. Well worth the cost!

By Josh M on February 15, 2018 | Verified Owner

Holley makes a comprehensive kit! I’ve used a self tuning kit from FiTech as well, and the Holley Sniper kit Includes a lot more of the bits and pieces one would need of starting from scratch. The only annoying thing I found lacking is the usb cable for a direct laptop connection, that’s an extra $50 from Holley. Otherwise you have to pull the sd card from the monitor and plug it into the laptop to view data logging or modify the fuel map and timing curve on the free Holley Sniper tuning software available online. It’s pretty easy to setup and fine tune. I used timing control on my project, if you use a stand alone distributor it would be a very quick and easy install and setup. I converted an Excalibur Cobra from the factory 1994 Ford 5.0 fuel injection it came with to the Sniper injection for a more retro look and easier tuning. More involved than replacing a carburetor, but worked out great. Smooth idle, even with a large cam, and great throttle response. I have already recommended Sniper Injection to a my friends.

Works Great

By Benjamin P on February 15, 2018 | Verified Owner

Updated Review: Apparently several issues were caused by mistakes during install. Holley has been good about working with me to get things corrected. After initially running well, I have had constant issues. Ended up having to remove the unit from the vehicle and go back to a carb.

great results on a 68 firebird 400

By stephen m on February 16, 2018 | Verified Owner

it has been a very easy install, great to work with. works great with the intank holley fuel pump. only problem is that here in montana I can't take it out on the road and really work it, just need the snow to go away. looks great, ram air induction mates up good. I am ready to go.

better than anything else out there

By Gary H on February 16, 2018

The computer interface is easy to use, and easy to change the settings of

Great package

By jesus g on February 16, 2018 | Verified Owner

This sniper is awesome. It looks amazing and is packaged well. Easy install and definitely more power.

Dustin

By Dustin F on February 16, 2018 | Verified Owner

So far all is good. Have not yet ran on vehichle, but quality of product and ease of install with directions so far are pretty straightforward!

Upgrade your resto project

By Mark W on February 16, 2018 | Verified Owner

Adding this unit to restoration car leveraging sniper tank system makes easy for DYI guy like me

Sniper review

By Ken P on February 16, 2018 | Verified Owner

After waiting 2 months for the fuel tank, I’m finally getting it installed! I sure hope it lives up to all the good reviews!

Install was a breeze for the 69 Mach 1

By Ryan R on February 16, 2018 | Verified Owner

Ordered my system along with sniper EFI fuel tank kit and the all in one fuel filter and regulator. Very simple install, the car started right up and is very reliable. Took the car on a road trip from San Diego to Tucson for the zip tie drags, No trouble the entire trip.Still playing with all of its features.

Great system. Great investment.

By Joel Y on February 16, 2018 | Verified Owner

I'll admit it, I'm terrible with carbs......I've never really been able to get them to run as good as I want. After fighting a bog in a Street Avenger carb for about 3 years, I had enough. I decided that moving into the correct millennium would probably be a good idea and went with the Sniper FI setup and a new fuel tank with a high-pressure pump (also a sniper tank). The system is great. Had a few hiccups to start out (why the rating was a 4) and had to send it back to Holley for repair. They were quick with the return and the support to get me on the road. There is a learning curve for these units, so be aware that you will need to read and learn to take full advantage of a great system at a great price. I highly recommend using a laptop for your tuning instead of relying on the handheld screen.

First time injection install......468 BB 77 Nova

By Bobby E on February 16, 2018 | Verified Owner

The Sniper came complete w/o the pump kit. I bought the tank and pump combination, hoses, fittings and clamps from Holley also. The hardest part of my install was fabricating a new trunk floor and bracing straps to replace a well where a fuel cell had been. The Sniper tank and pump fit perfectly. Make sure you make an access port to get at the pump and filter. The inline fuse, harness etc. are mounted inside under heater box. The only giveaway under the hood is inlet line is on drivers side with return on passenger. Now the good parts....... After setting up with handheld it started within two (2) seconds and dropped to a very good idle. After about 50 miles of self tuning I was sold on the Sniper. It would drop to the correct idle at a stop but then increase about 200 rpm but was fine until the next stop. I used the manual in the Idle section and corrected it easily. The throttle response is great ( from initial start) and I don't think I'll ever buy another carb. My job was a mechanic in electrical,fluids and refrigeration so install,plumbing etc, was easy Make sure you pay attention to Holleys photos of wiring. They know that most failures are shortcuts, junk connectors.THIS IS A GREAT SYSTEM. Starts good in 30 deg. weather. Thanks Holley.

Works Great

By Forrest F on February 16, 2018 | Verified Owner

I replaced an outdated TBI system. This solved all my problems.

Well worth it!

By Jeff M on February 18, 2018 | Verified Owner

Easy install, started right up and ran well. Went with intank pump, nice and quiet. Easy tune ability, can’t wait to get hundreds of miles on her. 468 BBC 600 HP Big Mutha Thumpr cam Tremec 5speed 3.73 12 bolt posi

You will Love this upgrade

By Rodney O on February 19, 2018 | Verified Owner

Bought the Sniper EFI and new gas tank with fuel pump. The cars runs great . I would recommend this set up . No warming up car to get to run turn the key starts right up.

Easy install, works perfect

By robert c on February 20, 2018 | Verified Owner

Very easy install and works as advertised

Perfect fit.

By Donald C on February 20, 2018 | Verified Owner

I purchased my sniper kit going on a year ago, I have had zero issues with it. I installed it on my 86 C10 with SBC 350, it’s easy plug and play features are perfect for the do it yourselfer’s. It took about an hour to install it, the self tune feature is perfect. I couldn’t be more pleased with the way it works and performs. I would highly recommend it to anyone who wants to upgrade!

Excellent System

By Trent M on February 26, 2018 | Verified Owner

I purchased the complete system with fuel tank for my 1966 Nova. I wasn't sure what direction I would go with engine combination, so I wanted a system that would work with my 327 or 406. The best part it looks good and works great.

Excellent Product

By Gilbert M on March 4, 2018 | Verified Owner

I purchases the system to run in a 1991 Ford F150. Replaced the original sequential system with a 302 Boss upgrade. A little shaky at first although the system learned quickly with excellent improvement. Overall, very satisfied and easy install.

Finally one that works

By Ralph R on March 26, 2018

I have had a 1967 Camaro since 1988. In 1992 I installed a holly two barrel TBI. It worked fine for about 20 years. It had to be adjusted all the time and had a problem with injector life. In 2012 I saw in Summit catalog a self contained EFI system by Professional Products, it was the only one on the market. I bought one and installed it. I had nothing but problems that the techs tried to help me with. It turns out the problems could not be fixed and they pulled the Powerjection III system from the market. In 2015 I bought an FiTech EFI unit, it had problems with high RPM starting and a long time to decay to idle speed. It also would allow the engine to stall after coasting in gear and then pushing in the clutch. Their techs told me I was one of a few people with the issue and they were not going to upgrade their software. I was totally frustrated when I noticed in Summit catalog that Holley had the Sniper EFI system. The Sniper was the easiest to install and has the fewest settings to be programmed. The performance is better than any of the other systems. My only complaint is that Holley should have come out with their product a lot sooner. Ralph Ruggiero

Q-jet to Sniper. 400 small block pontiac.

By Tyler J on May 2, 2018

I installed this onto a 1969 GTO and the kit was very well packaged and contained basically everything I needed. Beyond the fact that I also had to purchase a new intake manifold for this to work, everything was very simple to install. There were only a few things I really did not care for with the system. I wanted to keep the handheld unit tucked and hidden away, so thus I wanted to keep my factory temp sensor. I found autometer part 2283 has the proper thread pattern for the holley supplied temp sensor. The only other thing I still have not figured out is if it is possible to change units. I am familiar with tuning several other systems (efi live, hp tuners, haltech, moates, and several others) and the navigation is simple, but for me, lacking a few things I would expect. Overall, I would suggest this, if, like me, you are tired of dealing with a carb. With some more patience, I will figure this out, and with a little know how, you can get everything how you want without sacrificing what already exists on the vehicle.

LQ4 with Holley efi

By Larry S on October 31, 2018

This does not control spark and firing just fuel the way i understand.Am i right?

Great Upgrade for an Old Jeep CJ7!!

By Melvin H on November 30, 2018

Installed this unit on a fresh built AMC360 for my '84 CJ7 about a month ago. Install process was very simple for the EFI unit and wiring. The hardest part was the routing of the fuel lines and finding a good place to mount the fuel pump and filters. Ensure you attach your vacuum advance line to the correct port on the EFI unit or you might have some rough idle issues. Since the install I have been more and more impressed with the operation. Morning cold starts are not an issue any longer!! That is by far the best part. Time will tell if this was a wise decision, but so far I am very satisfied.

recherche distributeur Europe ou france ou italie

By rod r on May 6, 2019

Bonjour, je recherche distributeur Holley, pour moteur V8 Chevy 305 pour mon bateau. Merci

Sniper transformed my 1969 K20

By Mark P on June 15, 2019

I shopped around for a TB EFI system for a couple months. After reading review after review and asking friends for their opinions, I chose the Holley Sniper system. (BTW I have a few friends that are on NASCAR teams and they recommended Holley as well) I purchased the system along with the in tank return style fuel tank pump kit. My only criticism is that I would have liked a simpler way to select the correct/compatible in tank pump kit for the sniper EFI kit. I followed the instructions that accompany the kits to the letter, until I realized that I had purchased a in tank fuel pump kit that did not extend down to the bottom of my 13.5” deep tank. Fortunately I have some fab tools and skills and was able to extend the pump, bracket and return line to suit my requirements. One the tank mods were finished I started on the EFI TB installation. Once again I followed the directions explicitly. Everything went together very well. The only thing that was a bit confusing at the onset was that there were a few extra wiring harnesses that came with the kit, but was not made clear why or what they were for. (Holley, please label these and make mention of the optional harnesses in the instructions). After everything was installed, I again followed instructions on the prostrate programming and sequence. The engine fired up perfectly and ran through all the systems test as described. OMG! This is so much better than the older style carb! This truck starts and runs so much better! I am a big fan now. My advise is for you to take your time, follow the instructions, plan on 16 hours of install time if you don’t use short cuts and do it right. If you don’t care about wiring and fuel line routing appearance, a person could get it done in 8 hours. I highly recommend this system!

My only regret

By Tony C on September 17, 2020

I put this system on my boat with twin engines and I only regret not doing it when they first came out with a marine rating! I've messed with carbs for years and it's always hard to get them just right on a boat. The Sniper just simply worked. Idle reliability - engine dying while docking, and timing issues are gone! The other part is that I did have some questions as I did the retrofit and once again, Holley tech support is second to none. Great people to work with.

Pretty good system

By JAMES K on June 5, 2021 | Verified Owner

Decided to try the Sniper after comparing reviews and so on of it and the FiTech. Put it on the fairly mild (370HP) 302 in my '72 F100, as a prelude to trying the swap on one of my serious engine projects. Very easy install. Have had a couple of items fail in the 5 or so months I have had it running. Holley was good about getting me an O2 sensor that failed, and the other part that failed was the included, no-name Chinese fuel pump relay, which I replaced with a better quality unit. It has some idiosyncracies, the most worriesome of which is some inconsistency. Today, for instance, upon first start, it was not doing it's usual job of enrichment and increased idle speed when cold. No idea why. Drove okay, and on the second start it seemed to be back on duty. The power is all there, but with the Sniper, the fuel mileage is poor compared to the carb and Mass-Air systems I previously had on it. I have set it to run a bit leaner than my preferences, but that hasn't helped at all. I intend to go through the settings on the Sniper yet again, and may change up ignition timing and spark plug heat range to see if that makes any difference with the Sniper. For a relatively low price, compared to many other systems, this is a fairly user-friendly system, and my old antique runs well with it the majority of the time. It's rather catch-as-catch-can getting a talented tech if you have an issue, but my second call for both issues that occurred did get answered by techs much more effective than those who answered my first calls. No insult intended to any of the techs...each one seemed more than willing to make sure my problem was solved and that I was satisfied. Hats off to Holley and their tech support. Vastly better than most of the tech support one has to deal with from time to time.

Good but Touchy Throttle

By Paco R on June 5, 2021 | Verified Owner

Works as advertised - nice installation. My only issue is that the throttle is very touchy at low opening. It makes it difficult to be smooth with a manual tranny. Otherwise great. Paco

Holley Sniper

By Marion F on July 26, 2021 | Verified Owner

Easy install, fired right up and idled. Excellent driving manners, looks to be getting better fuel mileage while burning cleaner and more crisp throttle response. Installed on my 454 c2 corvette.

Excellent, engine better then new

By Edward M on August 10, 2021

After an engine rebuild I Installed a sniper efi 4150 to my rover 3500 v8 engine in a landrover defender 1988. After studying forums gathering information and pieces to fit a new manifold and the sniper, the installation is pretty straightforward. Now the engine runs perfectly well. It performs almost 20 percent better then before. Cant wait to install the controlled ignition.

Impressed

By Jess N on November 30, 2021

This was a first time install for me so I followed the instructions to the letter. I still was confused so contacted tech service and Wesley took care of all my questions. When the unit malfunctioned he immediately sent return shipping info and had the unit repaired. The unit works as it should. I am impressed with Holley's service and the quality of the Fi unit. First start up of the unit went as the manual said it would. I will be a repeat customer.

Well built fuel injection upgrade

By Pete S on April 10, 2022

I looked at other brands of fuel injection systems before I decided on the Holley Sniper. I have used carburetors for many years. The throttle response is great. The throttle body kit and fuel delivery kit have quality parts. The installation information available online really helped fine tuning the system. The Holley techs are very helpful and easy to talk to.