Abstract: A porting apparatus in an internal combustion engine delivers and exhausts gas in a combustion space. A pair of cylinders each have a cylinder wall mounted for rotation within a head of an engine block. The cylinders each provide a pair of apertures in diametrically opposing and axially offset positions through the wall of the cylinder. A pair of rotatable manifold rods, each axially oriented, are each positioned within one of the cylinders. The manifold rods each provide a through port adapted for alignment with the pair of apertures of a corresponding one of the cylinders, such that within each of the cylinders and corresponding through ports, a gas flow is enabled for communication from one of the pair of apertures to the other of the pair of apertures through the through port upon each full rotation of the cylinders which are driven in coordination with the engine.