Disclosed is a modified valve guide for a four-stroke internal combustion engine that utilizes compressed air to accelerate outflow of exhaust gases from a combustion chamber and through the exhaust manifold. The device comprises a ported valve guide that is concentrically mounted about an exhaust valve stem. The valve guide is a hollow cylinder that surrounds the exhaust valve stem, and includes a vertically mounted port on its working end. Below the port is a circumferential ring and guide tube connection that accepts compressed air input, communicating forced air through the valve guide port on its working end into the combustion chamber and exhaust manifold. The introduction of forced air increases volumetric efficiency of the system by improving scavenging and forcibly removing exhaust gases from the cylinder during the exhaust stroke. Both the power and efficiency of the engine are improved, along with reduced emissions from the engine exhaust.