an internal combustion engine of the valve - in - head type having a low profile cylinder head which requires minimal headroom 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 .