Our next project was installing the MSD Atomic fuel pump and filter, which came with our complete kit. Also included in the kit was flexible hose rated for the higher (45 psi) pressure required for EFI. It should be noted that 100 percent hardline isn’t recommended for this installation as the flexible line helps absorb the pump pulsing. Of course there’s always a need for a flexible connection from the chassis to the motor, regardless of the induction system.

We found a suitable location for the pump under the car and slightly below the level of fuel tank. After safely draining and containing the fuel, the lines were cut and the pump was spliced into the feed. While there is an option for a single fuel line, we opted to run a return line back to the fuel tank, making our system a recirculating system. The constant recirculating fuel provides a cooler fuel.

The power for the fuel pump comes from the MSD Atomic Power Module so wiring and control is simple. There is also no need to install a pressure gauge as the supplied handheld controller enables you to adjust the fuel pressure electronically, how cool is that?

At this point we had the Atomic EFI system installed. A quick check of the fuel lines and wiring and linkages indicated we were ready to fire up the small-block. The battery was reconnected and we answered some very basic questions on the handheld controller. Then the key was turned on, the fuel pump powered up, and with a twist of the key the 350 fired to life and settled into a smooth idle. At this moment it is easy to become a believer in EFI. Because the MSD Atomic Fuel Injection is a self-learning system the need for fuel map tuning and throttle configuration is eliminated. There are advanced tuning capabilities built into the handheld controller, but for many street rodders the self-learning mode is as far as they go.

The MSD Atomic EFI does have some limitations. The unit is designed to operate engines producing more than 100 and less than 525 hp and the Atomic EFI unit will not work on dual-quad applications. Likewise the unit is designed for modern-day pump gas so alternative fuels and power boosters will not work with the throttle body.

The MSD Atomic EFI has the ability to control timing but it requires an MSD Ignition Control. Since the Atomic EFI does not have a built-in ignition driver your points or HEI distributor will require ignition box for the EFI to operate. The Atomic requires a trigger signal from the ignition in order to function. This can come from the tach output of a GM HEI distributor, most coil negative terminals, or from a 12V trigger source such as the tach output from a typical CD ignition control. In order to control the ignition timing through the Atomic, you would need to run a CD ignition control such as an MSD 6A.

While the MSD Atomic EFI can literally be installed in an afternoon, we’d plan on making a weekend conversion out of the job. Something we have become adept at lately is taking an afternoon job and squeezing it into a weekend. But regardless of whether you are quick enough to do it in four hours or twelve, the results are well worth the effort. Quicker starts, smooth idling, superior driveability, mileage, power, and cleaner emissions add up to huge improvements, making this one of the best modifications anyone can make to a street rod. Now follow along with the photos and we’ll show you how it’s done.

There are ample vacuum ports made available on the Atomic EFI, up front we used the large port for the PCV hose, while the smaller hose on the left controls the vacuum advance on the distributor.

The PCV hose was gently touching the throttle return spring so the guys at Hot Rods by Dean came up with this clever Ty-wrap bracket. A large wire end bolted to the EFI base does the trick.

The temperature sending unit was next up and once again a plug on the wiring harness simply plugs to the sensor.

Speaking of wiring, here is the wiring diagram from MSD, it illustrates just how simple the electrical portion of this install really is.

The only fabrication involved was installing the bung for the O2 sensor (some headers have this on the collector already). After a pilot hole, the step drill does a nice job of cutting a round hole.

The bung was TIG welded in place and you’ll note that the sensor is located on a straight portion of the tubing. This is important for correct readings, likewise be certain you have no exhaust leaks upstream of this sensor.

Once again the O2 sensor simply plugs into the supplied harness with the weather-tight connector.

The Atomic EFI comes with a short cable from the power module to the handheld unit so you can do the basic setup function on the fender.

However with the optional long extension the handheld unit can be used inside the car, this can be handy for advanced tuning, although many street rodders simply set the basics, set it and forget it.

The initial setup asks some basic questions about the engine and transmission. If you can read this story you can set up the Atomic EFI. You can adjust everything from fuel pressure to a rev limiter in the basic format.

There are advanced settings and a troubleshooting screen all on the handheld device; this is a very user-friendly system.