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Dodge 318 Performance Upgrades - More Horsepower Made Easy

By Edited Jan 23, 2016 2 0

The Dodge 318 small block is an incredibly common V8 engine found in many Dodge and Chrysler cars and trucks. Although it was initially designed as a more fuel-efficient version of the mighty 360, you can get gobs of horsepower and torque out of the 318. These Dodge 318 Performance Upgrades range from simple to complex, cheap to expensive and even cover all years of Dodge 318 engines, ranging from the naturally aspired (carbureted) motors of yesteryear to the technologically advanced, fuel injected engines found on newer vehicles.

Dodge 318 Engine 2

Dodge 318 Performance Chips

If your vehicle is computer controlled, an aftermarket computer chip is probably the easiest, fastest and maybe even the cheapest upgrade you'll ever make. Dollar for dollar, you can't beat the performance gains of a new chip.

Obviously this won't apply to non-computerized engines, such as those with carburetors. But if your car or truck can benefit from a high performance, make this first on your list. Besides, with on most modern cars, it's nearly impossible to upgrade the actual physical engine parts - either because it will mess with the emissions or flat-out won't work.

Don't have a computer-controlled 318 engine? You've Got Plenty Of Options

While older engines won't benefit from a new chip (probably because they don't have them at all), you can still get plenty of additional power. While you'll need to get your hands dirty - and in many instances, plenty of mechanic experience and/or access to a well-qualified professional mechanic.

Dodge 318 Ignition Upgrades

Depending on the age of your motor, you'll either be looking at a points-type ignition system or an electronic ignition system. The later is far superior to the former, which relied on mechanical timing and vacuum pressure to ensure correct time. If you have an older ignition system, simply swapping in an electronic ignition system can boost your lower end torque, upper RPM horsepower and even increase fuel efficiency. Not many upgrades will give you all three (most sacrifice economy at the expense of power, or vica versa), so it makes sense to take advantage of this upgrade if you're running an older system.

The ignition system on a Dodge 318 motor is no different than any other engine. You've got several parts working together to provide "spark" to fuel mixture once it enters the engine's combustion chambers:

  • Ignition Controller
  • Coil(s)
  • Distributor
  • Spark Plugs
  • Spark Plug Wires

Upgrading any of these parts can provide some decent power gains, but I'd recommend starting from the top of this list and working down - or overhauling the entire system at once. High performance spark plugs won't make a very big difference if they're still drawing their juice from an inadequate ignition controller or coil.

Dodge 318 Performance Camshafts

Dodge 318 Engine 2
The camshaft is widely considered the internal "brain" of the engine, because it effectively dictates the way your motor breathes. The camshaft is responsible for opening and closing the intake valves and exhaust valves, and also determines how long those valves stay open.

Most cars and trucks are designed for a good mix of performance and fuel efficiency, so if you don't mind losing some fuel efficiency, you can realize some very substantial horsepower gains with a performance camshaft.

As you shop for a high performance camshaft, resist the temptation to go for all-out upper-end horsepower, unless you are only planning on using this engine on a race track. Not only are professional grade camshafts often illegal (for emissions purposes), they are horrible for road cars. They don't provide enough vacuum or low-end torque to stay running at idle or to smoothly accelerate from stoplights.

Dodge 318 Performance Heads

If a camshaft is the "brain" of the engine, the engine heads are the "lungs." Not only do they provide the top-end of the combustion chamber, they also contain the valves and valve linkage. When the valves open, air is pushed through small openings - or "ports." The bigger the port, the more air-fuel mixture or exhaust vapors can move.

Typically, factory small block Dodge V8 heads provide a great mix of performance and daily drivability. New heads with bigger ports allow more air into the engine, which provides a bigger bang, which means more power. However, this comes at the cost of a big reduction in fuel efficiency.

Lots of companies make Dodge 318 performance heads, including Dodge itself (though it sells them under the "Mopar" monker - its racing and high-performance division).

Dodge 318 Performance Intake Manifold

The intake manifold carries the air fuel mixture from the carburetor to the engine heads, and its design determines its performance. Intake manifolds come in two main varieties, single plenum and double plenum. Single plenums provide more upper RPM horsepower at the expense of low-end drivability and fuel efficiency, while double plenums provide more power in the typical street-driving range but top out as they approach higher RPMs.

While swapping out a performance intake manifold is one of the first modifications many people do on their 318s, I personally wouldn't do so before addressing the heads and camshaft. A performance intake manifold won't add much to an otherwise stock engine, and it could actually reduce performance.

Dodge 318 Performance Carburetors

It seems like everybody and their dog makes carburetors, and most die-hard fanatics have their favorite brand. I personally think that all aftermarket carburetors have their advantages, but that's not to say that the stock carburetors are all that bad.

If you've got a two-barrel carburetor, you might be able to find a four-barrel version at a wrecking yard or at a used auto parts shop. A four-barrel carb runs like a standard two-barrel carb most of the time, but when you mash the accelerator pedal to the floor, the back two barrels open up and allow gobs of additional fuel into the engine, providing more power (and killing your gas mileage).

Of course you can also buy high performance four-barrel carburetors at nearly any engine shop or auto parts store.

Dodge 318 Performance Exhaust Systems

The exhaust system includes several parts that work together to take the burnt air/fuel mixture from the engine to the exhaust pipe. After the fuel is burned, it exits the exhaust port and then travels through:

  1. Exhaust Manifold or Header
  2. Muffler
  3. Catalytic Converter (if applicable)

The overall goal of an efficient exhaust system is low restriction. You want the exhaust to flow through with the minimal amount of back pressure (note: Many enthusiasts say a little back pressure is good, but every study I've read, plus my own experiences working on engines prove otherwise, but to each their own).

For daily driver cars and trucks, it's tough to beat the original exhaust manifolds that came with the Dodge 318. If you're looking for horsepower, swapping in exhaust headers will probably help.

Final Thoughts

While many peole don't consider the Dodge 318 a "hot rod" engine, you can certainly get plenty of additional power with some simple performance upgrades.

If you want a high performance Dodge small block "out of a box," you might be interested in a Dodge 318 Crate Engine. They're built by professionals, which means all parts work well together.

But remember, everything is give-take. If you want high RPM horsepower (like muscle cars or racing engines), you'll sacrifice low-end drivability - which means it will make a horrible daily driver. Not to mention you might really mess up your emissions, making your modified engine illegal on the street. So be sure to do your homework before making any Dodge 318 Performance Upgrades.



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