Anyone can appreciate a classic car from an aesthetic perspective. In decades past, manufacturers didn’t have to conform to as many safety standards as they do today. While this objectively makes classic cars less safe than modern cars, it meant that designers had more freedom to design cars that just looked good above all else.

However, while classic cars might look more attractive and distinctive than modern cars, the actual technology that goes into classic cars is usually inferior compared to modern stuff. Fuel pumps are one example of this; classic cars tend to use mechanical fuel pumps, which are generally less powerful than electric pumps.

In this article, we’ll explain the advantages and disadvantages of mechanical and electric fuel pumps, and explain how you can swap out the mechanical fuel pump on your classic car for an electric one.

Mechanical vs. Electric Fuel Pumps: What’s the Difference?

Before we get into how to install an electric fuel pump in your vehicle, it might be worth it to go over the advantages and disadvantages of each kind of pump. While electric fuel pumps are generally better, it’s not always necessary to use one.

For any carbureted engines that haven’t been tuned for performance, a mechanical fuel pump will probably do the job just fine. The main disadvantage of mechanical fuel pumps compared to electric ones is that they can’t provide as much fuel pressure or fuel flow, but for everyday street driving they should work fine with most classic cars.

The advantage of using a mechanical fuel pump is that they’re cheaper than electric fuel pumps and a lot easier to install. However, if the engine in your car is boosted via a turbo/supercharger or if the engine uses direct injection, you’ll need an electric fuel pump to provide the necessary fuel pressure.

Using an electric fuel pump with a carbureted engine also has some other advantages over a mechanical pump. For one, using an electric pump can prevent vapor lock since it can deliver fuel at higher pressures than a mechanical pump. The more reliable fuel flow of an electric pump can also smooth out your engine idle and improve torque.

So, as for whether you should install a mechanical or an electric fuel pump in your classic car, this really depends on how easily you want to install the fuel pump and what you’ll actually be using the car for.

How to Convert a Mechanical Fuel Pump to Electric

Now that we’ve talked about the differences between mechanical and electric fuel pumps, let’s go over how to actually do this conversion yourself. 

One thing you might want to consider when installing an electric fuel pump is whether or not you want to keep the original mechanical fuel pump in place as a redundancy in case the electric pump fails. If you really want to, this is totally doable, but it will add a lot of complexity to the conversion process. Plus, electric fuel pumps usually last pretty long anyway.

For this article, we’re going to assume that you’re removing your mechanical fuel pump entirely. If that’s the case, here’s what you need to do:

Step 1: Preparation

Because you’ll be doing some wiring in just a bit, you should start by disconnecting the negative cable from your car’s battery to prevent an electric shock. You should also open your gas cap, as this will release the pressure from the fuel lines.

If you need help getting the pressure out, you can pump your gas pedal a few times to relieve some more pressure after opening the gas cap.

Step 2: Disconnecting the Fuel Lines

Next, find the fuel lines connecting the tank to the mechanical fuel pump. The fuel pump will likely be located in the engine bay, near the front of the engine block and close to the bottom. The fuel lines will probably be held in place with hose clamps. Place something under the fuel pump to catch any spilled fuel, then pull the hoses off the fuel pump.

Step 3: Disabling the Mechanical Pump

It’s not necessary to remove the whole fuel pump from the car if you’re installing an electric one, but you need to make sure that the mechanical pump is entirely non-operational before you do so. 

To that end, you need to remove the fuel line from the mechanical pump to the carburetor, and then plug up any holes in the mechanical pump with hose stops. 

Step 4: Installing the Electric Pump

The electric pump needs to be installed in a relatively low spot on the car, as this makes it easier for fuel to enter the pump and prevents the pump from wearing out prematurely. An electric fuel pump also needs to be mounted as close to the fuel tank as possible. If you’re able to install the fuel pump under the fuel tank, this will be ideal.

Your electric fuel pump should include a mounting bracket to allow you to install it easily, and there will likely be an arrow on the pump as well letting you know which way the pump should be mounted.

Step 5: Grounding the Fuel Pump

Next, you need to ground the electric pump by attaching the black wire to the car’s frame. You can do this by removing a bolt that is close by, passing the bolt through the pump’s ring terminal, and then reattaching the bolt to the car.

Next, you need to attach the red (positive) wire to your car’s fusebox to provide power to the pump. You’ll probably need to splice a piece of #12 wire onto the pump’s red wire in order to do this.

Step 6: Reconnect the Fuel Lines

Finally, you’ll need to hook up the electric pump to the fuel lines. All you need to do is attach the fuel line from the fuel tank to your new pump, and from the new pump to the carburetor.

You may also want to install some fuel filters along your fuel lines. You can do so by cutting the fuel lines and installing a filter at the gap in the lines. Make sure the fuel filter is facing the right way when you install it.