An internal combustion engine of the valve-in-head type having a low profile cylinder head which requires minimal head-room in the engine compartment of an automotive vehicle The cylinder head has a rectilinear configuration with the valve trains disposed on horizontal axes extending transversely of the cylinder head. Each valve train in the cylinder head is provided with precise axial support at both ends of the train. The engine has a relatively thin upstanding combustion chamber over each cylinder and one or more pairs of poppet valves per cylinder each having a sealing surface adjacent its outer edge for engagement with respective seats defined by axially aligned header tubes. Each valve has a relatively short neck extending through the combustion chamber during the intake and compression strokes and when the fuel-air mixture is fired. The valve spring of each valve train is situated between a fixed abutment attached to the side wall of the cylinder head and the end of the valve cage remote from the poppet valves.