Ford’s 300 cubic inch inline six-cylinder engine is one of the most popular engines in the world. With an excellent reputation for reliability and decades of production, the 300 six has provided loyal service to millions of truck and van owners.
While it can be rugged, the 4.9L I6 has never been better, delivering solid low-end torque but only average horsepower in stock form (with around 100 ponies and 220 lb-ft of twist in. its most powerful iteration). In most applications this is not a problem, as it was intended to provide affordable towing and hauling capabilities with modest fuel consumption, and after all, that was enough to help a Ford truck win the race. Baja 1000 no less than three times. Still, those looking for a power boost have traditionally gone for the swap and ditched one of the many Ford V8 engines that are directly suitable for any 300 CID 6 application.
However, a growing number of Ford fans are now choosing to follow a different path. In a world where small-block V8s are ubiquitous, building a 300 six for performance is one way to stand out from the crowd. Compared to even 10 years ago, there is an increasing amount of aftermarket support to extract more horsepower and torque from this oft-overlooked engine.
Curious about how to create a performance version of the Ford 300 inline 6 variety? Here are the 3 steps you can take to build more power.
(Note: We are going to avoid providing specific horsepower gains for each of these mods, as different combinations will give different results, especially on an engine as bottled up as the 4.9L six. Think of them as the base mods that you want to use. will want to do, and remember that you’ll have to adapt accordingly to take full advantage of what they bring to the table.)
1. Manifolds / Exhaust manifold
One of the main obstacles to producing horsepower with the Ford 300 six is its ability to breathe, and one of the easiest ways to improve its lung capacity is to install a manifold to replace the exhaust manifold. ‘origin. There are a number of different companies that make manifold designs for the Ford engine including Hooker, Hedman, and Clifford, most of which are long tube designs.
There is one major caveat to this tip though, and it involves comparing carbureted engines to fuel injected engines. The former will see major benefits with a manifold installation, but EFI engines already switch over very efficient exhaust manifolds and there is no benefit to replacing them. In fact, you’ll often see 300 six projects carbureted with EFI manifolds because they handle heat better than a long tube manifold and are significantly less expensive.
If you are using a full exhaust, an EFI manifold is a good choice in all areas. Spending more money on long tube headers for a carburetor build will result in additional gains, while those using a forced induction motor or full stroke motor will certainly want to exceed the standard manifold. Also keep in mind that maximum horsepower is only the tip of the iceberg. A good header or manifold upgrade can help an engine produce more midrange horsepower over the entire rev range than it would have in stock, resulting in a better driving experience. .
2. Intake manifold / carburetor
Equally important is that the Ford 300’s intake system is upgraded so that it takes full advantage of all exhaust mods. Most aftermarket intakes are aimed at making it easier to replace the original 1 barrel carburetor with a much more efficient 4 barrel unit, although it is possible to add a 2 barrel to the original intake through an adapter.
Companies offering six 4.9L intakes include Aussiespeed (both 2-barrel and 4-barrel), Offenhauser (the C-Series), Edelbrock Holman Moody, and Clifford (which even has a dual carburetor setup). Side-draft and down-draft manifolds are also available. Not all of these admissions are currently in production, but they are floating around the corner of someone’s garage or on the top shelf of an auto parts warehouse, if you dig.
We’re going to be breaking our “no specific horsepower forecast” rule to point out that with the right combination of intake and exhaust, you can easily add 60-75 horsepower to the 300 six, as well as an extra 50 lbs of torque. -pi. . We’re mentioning this because it’s an astonishing 60% improvement over the stock, given the engine’s modest baseline.
It is very possible to overload the engine, so don’t be too wild when choosing a 4 barrel. Make sure it matches the fuel needs of your build. If you stick with EFI, you’ll be disappointed to find that the factory is your only bet when it comes to intakes.
Given that it has been offered in so many different applications, it is no surprise that the list of camshaft grinding wheels available for the Ford 300 is long and distinguished. Companies ranging from Comp Cams to Crower to Isky to Crane build streetable camshafts ranging from 206/252 degrees up to 258/292 degrees. The stock Ford camshaft for a wide range of 300 I6 trucks is 192/268 degrees.
The most important thing when choosing a camshaft is to make sure that it matches the type of driving you plan to do. Shifting all of the performance up the end of the rev range doesn’t make much sense for a street 4.9, considering you’ll be sacrificing the smooth torque of the I6 to make it happen. If you are building a drag car, that’s another story.
Engine compression and the tuning ability to take advantage of the improved lift are also crucial. Therefore, if you are an EFI owner, you will want to upgrade to an aftermarket engine management system. Finally, don’t forget to upgrade the valve system to deal with any additional stress that might be placed on it by a more aggressive camshaft.