How to Get More Horsepower for the 1994 GMC 5.7 Liter TBI

by Justin Chen
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Chevy small block engines, such as the GMC 5.7-liter TBI, offer vehicle owners the opportunity to increase the engine’s horsepower output because of their popularity and durable construction. Although there are a variety of ways to increase the horsepower output of an engine, the safest and most effective way is through performance aftermarket replacement parts, higher quality maintenance and engine tuning.

Step 1

Fill up your vehicle with high octane fuel rated above 90 octane. Higher octane fuel burns more completely during combustion, resulting in higher power output. Higher octane fuel also typically increases the fuel economy of a vehicle because of its better combustion properties.

Step 2

Add fuel injector or carburetor cleaner to your vehicle's gas tank every 3,000 miles. This should be done on a nearly empty tank that should then be immediately filled to full to mix the cleaner into the gasoline. This ensures that the car receives adequate fuel at high engine speeds, increasing the amount of power each cylinder produces.

Step 3

Install a cold air intake on your vehicle's air intake manifold. This keeps air from becoming restricted on the way to the engine and keeps it cooler. Colder air is more conducive to burning than warmer air and gives a slight increase in horsepower.

Step 4

Replace the stock exhaust system with an aftermarket, 3-inch cat back exhaust kit from the exhaust manifold to the tailpipes. This allows exhaust to move out of the manifold quickly. The higher the air movement ratio in an engine, the more horsepower output there is.

Step 5

Install a performance camshaft to increase airflow and exhaust movement during combustion. Camshafts determine how far the valves open and let air in and out of the cylinders. Performance-rated camshafts will typically increase horsepower output by between 10 to 30 horsepower, depending on the camshaft purchased.

Step 6

Port the cylinder heads. This allows exhaust to escape the cylinders faster by removing metal from the engine where the exhaust manifold meets the cylinder heads. Exhaust gases can then move in a direct path to the exhaust manifold rather than having to bend around a corner to escape the cylinder.

Step 7

Tune the vehicle’s computer. A tune is an adjustment of a car's computer, making it optimally programmed for horsepower. This should only be done by an expert using advanced automotive computer programming software. You can remove the computer in your vehicle and send it to a tuning company by mail and get it back a few weeks later with a performance tune.

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