How to Increase Gas Mileage on a Chevy 454 Engby John Walker
The Chevy 454 first hit the market in the 1970s. The 454 is a big-block carbureted engine found in most older model Chevrolet cars and trucks. The engine uses eight cylinders to provide high-end torque and speeds. The combination of larger bore and eight cylinders equates to very poor gas mileage. The engine runs an average of 10 to 15 mpg. Increasing the gas mileage without sacrificing performance on the vehicle only requires inexpensive and simple changes to the engine.
Replace your current air filter with a high-flow dry or oiled air filter. Several manufacturers offer lifetime, high-flow air filters, which are available at any auto parts store. Simply remove your existing one by unscrewing the hold-down bolts and install the new one directly onto the engine.
Remove your spark plugs using a spark plug socket wrench. Install platinum quad-head or iridium spark plugs also available at any auto parts store. Disconnect the spark plug wire and replace each spark plug one at a time so as to not confuse the location of the wires. Reattach the spark plug wire before changing out the next plug.
Adjust your idle speed to the lowest setting. The idle screw is located on the side of the carburetor connected to the throttle cable. Adjust the screw with a Phillips-head screwdriver while the vehicle is running and warm. You want the idle to be around 800 to 900 rpm with the vehicle in park and around 700 rpm with the vehicle in neutral. Monitor your tachometer while adjusting. Adjust the idle by sound if you do not have a tachometer. Listen for the engine rpm to drop until just before it starts to sputter. You want the sound to be smooth without coughing or sputtering.
Tune up your vehicle. Dirty or poorly timed carburetors do not properly mix the fuel and air. A simple cleaning by spraying a carburetor cleaner into the open ports of the carburetor with the air filter removed and the vehicle running cleans the carburetors for increased performance and mileage. Routine maintenance and maintaining a low idle speed also increases performance and mileage.
Maintain the proper tire pressure in your vehicle. Check the pressure and ensure that it is at factory specifications. Lower tire pressure creates higher drag that forces more fuel to be consumed. Check the tire pressure weekly.
- Increased air flow and spark result in lower needs for fuel. Adjusting the idle mixture after completing will lower the amount of fuel consumed with standard driving. Wide-open throttle (flooring the gas pedal) will still consume extensive amounts of fuel, but with these changes, you will see an increase of 10 to 20 percent on your mileage. These methods are particularly effective on Chevy and Ford big block engines of all sizes.
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