Abstract: An engine constructed with a hemispherically shaped combustion chamber having inlet and exhaust valves flush mounted in the surface of the chamber with centerlines perpendicular to the chamber surface and intersecting the cylinder bore centerline at a common point; the valve train components for each valve all acting in a single plane and having centerlines that together converge towards a common point adjacent the cylinder bore centerline, the valve train planes of each pair of inlet and exhaust valves being canted with respect to each other and to the camshaft axis, a single overhead camshaft being centrally located between the inlet and exhaust valves.