Holley Sniper EFI 550-511

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Holley Sniper EFI

Part # 550-511

16 Reviews

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About Holley Sniper EFI

Explore Sniper's high-performance fuel system products to build your affordable high-performance fuel system at Holley.com!

Accelerometer Support	No
Air Metering Style	Speed Density
Boost Control	No
Brand	Holley Sniper EFI
CAN-BUS Support	Yes
Category	Air and Fuel Delivery
Coil Per Cylinder Ignition Support	No
Datalogging Support	Yes
Distributor Included	No
Dry Nitrous Control	No
e85 Support	No
EGT Support	No
Emission Code	3
Forced Induction Support	Yes
Fuel Filter Included	No
Fuel Hose Included	No
Fuel Injectors Included	Yes
Fuel Pressure Regulator Included	No
Fuel Pump Included	No
Grade Type	Performance
Ignition Timing Control	Yes
Individual Cylinder Fuel Corrections	No
Intake Manifold Included	No
Knock Retard Support	No
Multi-Stage Nitrous Control	No
Part Type	Fuel Injection Conversion Kit
Progressive Nitrous Control	No
Self-Tuning	Yes
Sub Category	Service Kits
Throttle Position Sensor Included	Yes
Traction Control Support	No
User-Tuneable	Yes
Warranty	Two Year Standard, Extended Via Product Registration
Wet Nitrous Control	No
UPC	090127729007
Part Number	550-511

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

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!

Quickstart Guide
Quickstart Guide

Instructions for Part# 550-511
Instructions for Part# 550-511

Sniper EFI SD Card Contents
Sniper EFI SD Card Contents

Instructions - 199r11369.pdf

Instructions - 199r11194.pdf

Instructions - 199r11193.pdf

Two Year Standard, Extended Via Product Registration: See Details

Have a question about this product?

Question
Can the Holley Sniper EFI control electric cooling fans? The fans would be an add on for a 1970 Mustang. Also, can the Sniper be programed to shut down the a/c compressor on full acceleration? Thanks. Rich Harden
By Richard H. on July 9, 2018
Answer
Great Question Richard, The answer is both. Here is a link to the instructions, check out page 17, it tells you what wires you will need to utilize for both functions. http://documents.holley.com/199r11031r.pdf
Helpful?
Question
I have dual exhaust all the way back, would an "H" pipe work for this system, or can i just put the o2 sensor on one side? Aslo does the handheld programmer have to stay connected for the system to work?
By Jeremy P. on March 10, 2018
Answer
Yes, we recommend installing the O2 sensor 8-12" down stream of the header collector, before the H merge in your exhaust system. After you program the ECU with the handheld, and do the initial throttle position and IAC set procedure, you can disconnect the handheld from the ECU.
Helpful?
Question
can the holley 550-511 be used in a boosted application, turbo or supercharger?
By Zaine N. on February 9, 2020
Answer
It does have a built in 2.5Bar MAP sensor, but we generally recommend the super sniper systems for Boosted applications.
Helpful?
Question
Will this fit on a Dodge 383engine?
By Chet W. on August 26, 2019
Answer
That question is hard to answer without knowing what year the engine is. That being said, if the engine has a 4150 Flange intake, then yes this Sniper EFI System will most certainly fit your application.
Helpful?

Reviews

4.8 out of 5 stars

5 star
81%
4 star
19%
3 star
0%
2 star
0%
1 star
0%

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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!

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.

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.

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.

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

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.

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.

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.

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.

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.

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

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.