The 4.9-liter engine has been Ford’s choice for the V-6 power plant in their Ford F-150 trucks since 1965. Since its inception, people have been trying to upgrade the truck's equipment to enhance the horsepower output in an effort to match the bigger V-8 engines available in the higher-priced F-150 models.
The main principle for creating horsepower is to get more air into the engine to improve the engine's ability to efficiently burn more fuel. The factory air intake is very restrictive because it is encased in plastic (late-model fuel-injected Fords) or in metal (early model carburetor Fords) with very small inlet holes to suck air into the filter. Modern high-flow air filters, commonly known as cold-air intakes, increase horsepower because they allow more air into the engine. K&N Filters claims their cold-air intakes will add over 10 horsepower on a late-model 4.9-liter engine.
If you choose to add more air into your 4.9-liter engine, you will need to increase the flow of fuel into the engine. If your engine is equipped with a carburetor, you can simply purchase a larger carburetor and install it onto the intake manifold. If your engine is equipped with a late-model throttle body, you have more options. You can purchase a computer programmer that will allow you to manipulate the fuel settings to push more fuel into the engine, or you can upgrade to a larger throttle body, which will automatically calibrate the computer to allow for more fuel. A programmer is a good idea if you intend to make more changes to a vehicle to add power. The programmer will allow additional changes to the computer, whereas a throttle body will only make the change once.
The F-150 is equipped with an exhaust pipe that collects each side of the exhaust manifold into one pipe that extends to the back of the vehicle. This is called a single exhaust and is extremely restrictive. If gas cannot escape from the vehicle, air cannot get into the vehicle. Installing a dual exhaust will allow gas to escape from the vehicle at a much faster pace. This allows a vehicle to increase horsepower dramatically when used in conjunction with high-flow mufflers. It's also a great way to give your 4.9-liter engine an aggressive exhaust note.
