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1965 Chevrolet Chevelle 502 MSD Atomic EFI Install - Atomic Blast

An old-school 502 Chevy gets a dose of new technology when we install MSD’s atomic electronic fuel injection.

Mark Lundquist Mar 9, 2013
1965 Chevrolet Chevelle 502 Msd Atomic Efi Install Parts 2/24

Unless you have been living under a rock, then you already know there are many benefits to running electronic fuel injection on your engine. If you are reading this mag from under a rock, then we will just tell you that EFI does the same basic job a carb does, but it’s much smarter at doing it. We know that taking off something you are very familiar with—for example, the carburetor—and replacing it with something computer controlled can take some gearheads out of their comfort zone. Yes, we are talking about adding a computer to the fuel system, but nowadays those computers are just little boxes with simple hand held tuners. It’s getting to a point that if you can use a smart phone, then you can use an EFI system.

1965 Chevrolet Chevelle 502 Msd Atomic Efi Install Engine Bay 3/24

1 This is what we started with, a basic 502/502 crate motor with an 850cfm Holley carb— pretty standard stuff in our mind. One thing to note is the car is utilizing an MSD ignition system, which has an isolated 12-volt square wave signal, or trigger output, that the EFI requires.

One of the simplest EFI systems to install and tune on the market is MSD’s Atomic Electronic Fuel Injection. The system is designed to replace four-barrel carburetors, thereby creating smoother, more reliable street and/or strip driving. The system is so simple it can usually be installed and programmed in one day. The programming is easy and logical, and the comprehensive instructions are a snap to read and understand. Even electronic upgrades in the future can be downloaded from MSD and loaded into your system to keep up with new technology and revisions.

Our patient for the transplant is a ’65 Chevelle SS with a stock GM ZZ502/502 crate motor. It was equipped with a Holley 850cfm street carb. The MSD system gives you a choice of using it with or without a fuel return line. Based on a condition chart supplied in the instructions, our application will use a return line.

We ordered the base kit (PN 2910), which comes with a throttle body, power module (with wide band O2 sensor), and handheld controller. MSD offers a master kit that has a standard fuel kit for motors rated to 525hp. We foresee possible upgrades to the 502 that may push its power output beyond that rating, so we needed to order the basic kit and the high horsepower fuel kit (PN 2921) that will support 620 hp at the crank.

As an added bonus, the HP pump kit comes configured with a type of fitting that closely matched our current system. Since we will be adding a return line, we needed a few items not offered in the MSD kit. We got the bulk of our items from Summit Racing. Summit had just about everything we needed from the regulator to the fuel line. The last piece of the return line puzzle was a gas tank-sending unit that had a return line already in place. Not something you find everyday, but Classic Car Auto Parts had what was needed.

We spent a day installing the products and found it pretty simple to install, even with us adding a return line to the system. Once everything was bolted on and wired up, a short road test was in order. The Chevelle started immediately and ran great, so we felt confident enough to take her on a longer test and this is where the self-learning function took over.

It automatically made any necessary adjustments needed. We have to say the old ’65 has never run better. Follow along with us as we go through the steps to a modern upgrade for a classic Chevy.

Price Description Part Number
$1,990.00 Atomic EFI throttle body kit 2910
$599.00 High Horsepower fuel kit 2921
$20.99 3/8-inch 50psi rated rubber fuel line GTR 65128
$35.96 O2 sensor clamp AVM 302355300
$45.95 Fuel Cooler Flex-O-Lite 4130
$169.95 Aeromotive fuel pressure regulator AEI 13105
$79.00 Gas tank sending unit S-37CH238
Total $2,940.85


Summit Racing
Akron, OH
Classic Car Auto Parts

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