If you remember your American history, the Manhattan Project was the code name given to the development of the first atomic bomb that eventually helped end the war with Japan in 1945. Perhaps it's more than coincidence that Bob Kleiner chose to install MSD's Atomic EFI on his big-block Chevy-powered '54 Kaiser Manhattan to replace a carburetor. How well did this conversion work? On long cross-country road trips, the carburetor delivered anywhere from 15 to 17 mpg. With the MSD Atomic installed, the big-block's mileage jumped to a best of 20.8. Using the 17 mpg as the baseline, that's still a 22 percent improvement in fuel mileage. Plus, Kleiner says the throttle response is better and it's more fun to drive.

The plan was simple and the installation equally easy. Swapping the carburetor for the Atomic EFI throttle body was the easiest part. What took a little more time was converting the fuel delivery system over to create the necessary fuel pressure. There are plenty of ways to do this, but it turned out that the most efficient and easiest way was to use Aeromotive's new Phantom universal in-tank EFI fuel pump kit. We'll include a couple of install photos in this story, with an entire Phantom installation in a separate story that's also on the STREET RODDER website.

One of the reasons Kleiner chose the Atomic EFI system is because it offers ignition control. To take advantage of this option, the only real change you have to make is to lock out the distributor mechanical advance curve. Bob chose to install an MSD Billet lockout distributor, but any MSD distributor can be locked out simply by removing the distributor shaft and relocating the advance pin into the locked position. Then, using the Atomic's handheld programmer, you can get specific with the ignition curve. You still set the initial timing the same way, but the Atomic then controls the curves based on your inputs. It's a very slick option that does not require any additional electronic components.

It's important to note why the fuel delivery system is so important for EFI. Carburetors use a float system to maintain a constant fuel supply for the engine. When converting to EFI, the system requires high pressure—generally around 43 psi—at all times. Older cars with stock fuel tanks use a simple pickup tube placed near the front of the tank. This works fine for a carburetor, but with EFI, once the fuel level drops below half-full, fuel slosh can uncover the pickup. When this happens, the fuel pump sucks air, and the pressure immediately drops. This will result in a pronounced sag in engine performance. The OE manufactures solved this issue by building a reservoir around the fuel pump in the tank, ensuring there is a ready supply of fuel at the pump at all times. So if you are considering an aftermarket fuel injection system like the MSD Atomic, our suggestion is to do what Kleiner did and install the Phantom system in a new tank. It will work flawlessly and will create a much cleaner and more efficient fuel delivery system that will help any EFI system work like it should.

We'll run through some of the details involved with installing the MSD Atomic on Kleiner's Manhattan and show you just how easy it is to transform a carbureted street rod to 21st century technology.

DescriptionPNSourcePrice
MSD Atomic EFI base system2910Summit Racing$2,125.95
MSD Pro Billet distributor8361Summit Racing219.97
MSD Pro Billet dist., locked out85501Summit Racing265.97
Aeromotive Phantom pump kit18688Summit Racing537.97
Painless Roll-Over Cut-off80160Summit Racing111.97
Painless 8-pt. dist. block, red80114Summit Racing38.97
Billet Specialties dist. clamp65920Summit Racing24.97
Derale Atomic-Cool trans cooler13950Summit Racing199.97


1. Bob Kleiner installed MSD's self-learning Atomic throttle body EFI system on his big-block–powered Kaiser Manhattan in a no-stress weekend effort. He was rewarded with not only better fuel mileage, but also a car that's now even more fun to drive.

2. This is MSD's base Atomic kit intended for cars that already have a return style, high-pressure fuel delivery system. The photo shows the throttle body, the power module that controls the fuel pump and electric fans, and the small, handheld tuner. The system comes with all the necessary hardware and wiring harnesses.

3. Kleiner elected to start at the rear with Aeromotive's Phantom in-tank fuel delivery system. We'll go into more detail in a separate story, but the pump assembly creates its own reservoir to keep the pump constantly immersed in fuel. This maintains constant fuel pressure at the throttle body. The top of the assembly offers a high-pressure outlet, a return, and a separate vent location.

4. At this point, Kleiner has already cut the hole in the tank for the pump assembly. The pump is surrounded by fuel cell foam that prevents fuel slosh, maintaining constant fuel pressure. When properly installed, this system will function right down to the last one or 2 gallons of fuel in the tank. Kleiner also installed a Painless cutout switch that will kill the power to the fuel pump should the car accidently roll over.

5. Kleiner chose a suitable location for the fuel pressure regulator on the firewall and routed his fuel lines up to the regulator. Kleiner has routed his fuel lines to run directly from the pump to one side of the Atomic throttle body. The outlet side of the Atomic is plumbed to the regulator, which then returns fuel to the tank.

6. The MSD Atomic throttle body is rated at 1,000 cfm and can support up to 625 hp through its four fuel injectors. The throttle shaft rides on ball bearings for smooth operation. The MSD also integrates the ECU into the throttle body itself, which minimizes the external wiring.

7. Dropping in the Atomic throttle body is a simple swap for the original carburetor. The Atomic is also fitted with multiple vacuum outlets for PCV, power brakes, and a vacuum advance unit.