Sniper Stealth Install: ’69 Chevelle with Sniper Stealth EFI

Posted by Chris Myer 06/18/20 0 Comment(s) Customer Rides,


As the COVID-19 pandemic brought the regular routines of work and travel to a screeching halt, many car enthusiasts found extra time to work on their custom projects. That has certainly been the case for our friend, Larry Mazzola of Long Island, New York. Larry owns his own shop, ProWorx Performance (Instagram account), specializing in auto repair and custom upgrades for older cars, but has recently found time to make some great progress on rebuilding his 1969 Chevelle. We had the chance to catch up with him over the phone and hear about his experience converting this classic from a carburetor to the Holley Sniper Stealth 4150 EFI system.


Larry came to EFI System Pro wanting to take advantage of EFI technology while keeping a stock look as much as possible. This has been his goal for the car since he bought it from his uncle 10 years ago. Since then, he has rebuilt the factory 396 big-block, added a 5-speed transmission, and run a few different carburetors including a custom-built race carburetor that was pretty well dialed in. That being the case, Larry knew there was still more opportunity on the table with electronic fuel injection. With these goals in mind, we advised Larry to go with the Holley Sniper Stealth 4150 EFI system. In addition to the EFI system, Larry also picked up an OE-Style fuel tank module, a HyperSpark distributor, a set of Holley gauges for fuel pressure, oil pressure, voltage, and coolant. He also picked up a Sniper EFI Throttle Lever Extension to ensure a smooth throttle response.


“I went with EFI, because I like the technology, the ability to laptop tune it or to just tune it with the handheld display. I liked the simplicity of it. You don’t have to wait for the choke to kick on, you just turn the key and it starts.”


“I’m very OCD.  The car is far from stock, but it looks stock.  I installed the control box in place of the original washer tank mount.  I hid the EFI wires by running them along one of the existing wiring harnesses.  For the fuel line I took the fuel pump rod out but left the original fuel pump in place with the original steel fuel line to the carburetor location.  Chris gave me some great information on this and helped me avoid what might have been a problem with turbulence.  I used the original distribution block but actually drilled through it and ran stainless steel lines through it.”


Larry has been very pleased with the Holley HyperSpark distributor as well! “What a genius idea that is. The technology is great. I would definitely tell anybody, you can keep the stock appearance, why not use the technology if it is there?


Installation Pictures:




Original fuel lines customized to work with the Sniper Stealth Throttle Body


New Holley gauges and a custom-built mount for the LED handheld display.


How would you describe the installation process, Larry?
“It was probably one of the easiest things I’ve done. It’s really amazing how easy it is.”


What benefits have you seen so far from the system?
“Better power, a lot more responsiveness, better drivability, the system is constantly correcting itself. Even with the system not being fully learned I am feeling more performance than the race carburetor.”


We are glad to hear of the success Larry has had with his Holley Sniper Stealth EFI System and are glad to have been along for the ride from choosing the right system and all the way through the installation.


Check out these great pictures of Larry’s ’69 Chevelle taken by his son out at Pilgrim State, an abandoned psychiatric center on Long Island!






American muscle at its finest!


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Customer Reviews
John Frey
EFI System Pro had everything I needed for my EFI upgrade. Pricing was reasonable, shipping was prompt and Chris helped me with a wiring question during my install. The Tech Tips and discussions are also great!
Posted 05/01/2020
James Campbell
Super informative, fast shipping, and so far a 5/5 experience! Strongly recommend.
Posted 01/09/2020
Christopher McCloskey
The Ordering process was so easy and non-painful. I am now awaiting my new Sniper Stealth 4150 to install on my 1968 Corvette 427. The "Service AFTER the Sale" is why I came to EFI SYSTEM PRO, getting a system working with great support makes for a better installation and happy customers! I strongly recommend EFI System Pro.
Posted 03/13/2020
Jay Wilkins
Super helpful and knowledgeable. Full product line and accessories at excellent pricing.
Posted 03/22/2020