The Relationship Between Valve Angles and Airflow

For the student of internal combustion, you’ve likely heard the oft-repeated line that an internal combustion engine is nothing more than an air pump. The reason that’s a cliché is because it’s true. The more air an engine can capture in the cylinders and then squeeze into making cylinder pressure, the more horsepower and torque it will make.

The title for this story might lead you to believe this is a treatise on valve seat angles. But it’s not. This story will instead focus on a far less popular but equally important topic of valve angles. We’re going to use the small-block Chevy family as our point of reference for this story because this engine has been around for over 60 years and has experienced a huge transition in valve angles.

Let’s start with its definition as the angle created between the centerline of the valve and the centerline of the cylinder. For the