You have a beast inside your Chevy engine just waiting to be let loose. To achieve the best results and increase your horsepower, you need to get everything working together in harmony. Modifications to the engine can increase horsepower, torque, acceleration, and towing capacity. Some might even get better fuel mileage out of your Chevy engines.
While some of the hacks on our list are simple, inexpensive fixes that anyone can perform, there are some that are slightly more advanced. Use common sense and hire a professional if there is a job to be done outside of your expertise.
Now, let’s unleash the power within those Chevy engines!
It’s true than an after-market exhaust system will be less restrictive than your factory system. With that said, this doesn’t always mean that adding an exhaust system to your vehicle will result in additional power. Depending on the engine and exhaust system you settle on, you could see as much as an additional 50 horsepower to as little as two horsepower. This is exactly why it’s important to make a wise decision on your choice of exhausts.
The performance estimates given are normally on the generous side. If you find a Flowmaster kit that says it will add eight horsepower and a Magnaflow kit that claims to add 13 horsepower, you can pretty much bet they are going to add close to the same amount.
The safe assumption is that you’ll gain anywhere from two to five-percent more power by adding a new exhaust system. Larger 6.0-liter V8 Chevy engines usually see up to a three percent increase while a smaller 1.8-liter 4-cylinder engine is going to see anywhere from three to five percent.
It’s important to clarify that you can multiply the effect with other additions. While the exhaust itself isn’t going to add gobs of power, when it is combined with other performance add-ons like an air intake, you’ll see a significant increase.
Let’s be honest for a minute; adding a new exhaust has other perks as well. Not only can you achieve better fuel economy, but you’ll have a sporty exhaust note, a superior throttle response and driving might just become more enjoyable.
Ask any Chevy enthusiast how he (or she) got more power and they’ll likely tell you to port the cylinder heads. This process involves enlarging either the intake or exhaust ports to increase the overall airflow capacity. This can also involve smoothing out the passages and removing the cast-in impediments of airflow.
While most novices can accomplish this work at home, you might want to talk to an expert before you begin grinding. If you remove too much of the material, or you remove it from the wrong location, it could actually cost you horsepower. If you have rectangular port big-block heads, we don’t recommend touching them at all.
By the way, while the heads are already off the engine, consider having them milled slightly to ensure they are free of any warping. This also provides a little more compression which results in higher horsepower. At about 0.040-inch flat-mill on the deck surface, you can expect a full point rise in the compression ratio. This will achieve about 5-percent more horsepower but is awfully aggressive. You are better off going with 0.020- or 0.025-inch spec so you have a thick deck plus good piston-to-valve clearance.
Your stock intake manifold wasn’t designed to be powerful; it was created to be functional. Upgrading the intake increases horsepower and it can also change the rpm range where most of the horsepower is created.
The aftermarket manufacturers spend most of their time researching ways to improve upon factory products. The first area that happens in is the intake runners. These individual passages feed the combustion chamber of each cylinder. In a stock intake manifold, these runners are often undersized. They could also have been cast with restrictive bends that are sharp. You can find aftermarket products with varying runner diameters to suit your particular needs.
It’s also important to be aware that there are some companies that make manifolds with the air gap feature. In a stock manifold, the heat rises and your manifold absorbs the heat. This gives you a warmer air and fuel charge which results in less horsepower. With the air gap feature, you have a space between the oil valley of your engine and the lower intake. This gives you a lower temperature which naturally increases the power.
Installing your own intake manifold is straightforward. What is most intimidating is dealing with a tight engine bay, but it doesn’t have to be. With some basic tools and general knowledge of mechanics, you can swap out the intake manifold in a day. Of course, if this is something you aren’t comfortable with, most reputable shops can handle it instead.
If you have an older ride, installing an aftermarket carburetor often makes a nice improvement in performance. Just keep in mind that a carburetor itself won’t add power unless you are under/over carbureted currently or you are under/over jetted. Stock motors with stock carbs can benefit greatly from an upgrade.
You might always want to think about a phenolic riser. This will put the carburetor an inch above your intake manifold to generate more velocity with the air/fuel mixture. It also puts the carburetor further from the heat so it mixes cooler air with the fuel.
Performance Cam Shaft
Performance cams can increase the timing and duration of the valve opening during engine stroke, thereby increasing the horsepower and allowing your vehicle to accelerate faster. The idle is often a little rougher with a performance cam, but it does give that throaty rumble so many of us gearheads love.
Keep in mind that performance camshafts are one of your more expensive options, but they work great when paired with an exhaust or header upgrade.
To install your own performance camshaft on your Chevy engines, you need to expose the valve train. Do this by removing the covers and maybe even the distributor. Then, loosen the timing chain so it can be removed. Install the new camshaft and adjust the timing as necessary.
Not that long ago, if you wanted to change the parameters of your computer chip, you had to install a new one. That isn’t the case anymore since there is software that can make changes with just a few simple keystrokes.
If your Chevy engine is computer-controlled, you can use a handheld programmer to optimize the fuel delivery, advance timing and alter the shift points of an automatic transmission. Most manufacturers are conservative when they program the ECU (engine control units), so you can expect that it isn’t running at its capacity. The manufacturer is more concerned with emissions, fuel economy, and the vehicle warranty than power.
Remember that your ECU controls the air to fuel ratio, idle speed, ignition timing, RPMs, and valve timing. Drastic changes to your engine performance parameters can be tricky and you don’t want to mess with something you don’t understand.
Supercharger (Gas) or Upgraded Turbo (Diesel)
If you want more power out of your Chevy engines, it makes sense to research your super- and turbocharging options. A turbocharger is capable of adding more than 25% in power gains. Many turbocharger kits will run you about $3,000 for a common application and go up in price from there. They are also difficult for novice mechanics to install, so you’ll need to weigh the overall cost with the effectiveness to see if it is worth it for you.
A turbocharger sucks air into the engine which increases the horsepower and boost. You’ll need to also install an intercooler with your turbocharger so you can avoid turbo-lag. The intercooler cools the compressed air and reduces the temperature which increases the density of air going into the engine.
A supercharger is belt-driven so they are most effective for a six-plus cylinder engine. Superchargers aren’t going to require the use of an intercooler so the installation is easier. You can find superchargers in screw, roots-type, and centrifugal models depending on what engine you are using.
Increase Bore and Stroke
The block’s bore spacing, pan rail spacing, and cylinder wall thickness are all factors that determine how the engine can be stroked. This isn’t just important for stock blocks but also for the aftermarket ones as well.
When dealing with a standard 4.000-inch bore 350 block, many people find stroking it out to 383 ci as a popular option. They can accommodate an extra 0.030 inch of bore, so increasing the stroke from 3.480 to 3.750 inches means minimal block clearance. Going even farther to 3.8750 or 4.000 inches is also possible when discussing totals of 396 and 408 ci, but this creates more clearance issues among the camshaft, rods, and block.
An aftermarket block is a different beast altogether. With the taller deck height, thick cylinder walls, spread out oil pan rails, and raised camshaft tunnels, these engines can accommodate crazy displacement figures. Of course, the biggest reason people avoid aftermarket blocks is because of the price.
Even the most extreme do-it-yourselfer is probably not going to have their own honing machine or boring bar sitting around in the garage. This means you need to trust someone to do it for you. The only way to ensure a quality job is to thoroughly research the garage you take it to.
Dyno tuning is taking the computer chip adjustments to another level. This requires that a dynamometer is operated by a professional. This dynamometer runs like a treadmill for your car. It measures your torque and horsepower objectively.
Basically, the operator of the dynamometer starts off with a template for your vehicle. Then, sensors are hooked into the computer and the car is operated at maximum power. This allows the operator to adjust various settings such as your air to fuel ratio to unlock additional power.
The upside to this route is that the Dyno tune is based on your vehicle, not some cookie-cutter template. Before dealing with any shop on this adjustment, it is important that you discuss how the tune can be restored or changed in the future.
Ask anyone how to get power out of Chevy engines and inevitably you are going to hear about nitrous. This power in a bottle is an oxidizer, meaning that it adds more air. When this is coupled with more fuel, you end up with more power.
Kits range in cost anywhere from $900 to $3000 for most applications. They are also fairly easy to install if they are a basic kit, but the high-performance kits require a little more skill. Unlike a turbo or supercharger, you can take your nitrous kit with you to another vehicle, so you’ll never lose the investment.
Nitrous can also be used in conjunction with supercharging or turbocharging to increase top end speed and reduce lag.
If you are dealing with a typical V8 engine built for performance, start with a 75 HP shot and move up in 25 HP increments to 150 HP. Most stock engines can handle up to 100 HP safely, but it is best to start with 75 HP. Most performance-based engines can handle 150 HP without issue. With that in mind, you never want to go above that unless the clearances in the engine are set for nitrous use.
A Quick Word about Your Manufacturer’s Warranty
When discussing adding power to Chevy engines, one of the first questions is always related to the warranty. By law, vehicle manufacturers must prove that the modifications you make to a vehicle caused damage to the car for them to void your warranty. This means if you swap out the stock air box for an aftermarket intake, it’s possible that you could void the warranty on your airflow sensor because you changed a part relating to that system.
In short, you want to modify your car prudently and safely. If you discuss the options with your service advisor, they will probably tell you what you need to do to sidestep voiding the warranty. Many times they will gladly look the other way unless what you are altering is extreme.
For them to deny warranty service, they must have the proof that your modification was what caused damaged to the part that broke. Most of the time, the changes you are making won’t hurt the car. Be knowledgeable about what you are doing so you can defend yourself.
How Much Power Can You Get From Chevy Engines?
We would love to hear about your favorite ways to boost Chevy engines. Let us know in the comments and maybe it will make our next list!
Before you leave, take a look at this 260 Cubic Inch Chevy SB2 Making 1,000 Horsepower on Boost.