Some embodiments are directed to a valve assembly for use with a combustion engine. The valve assembly can include a valve stem having a plunger end, and a valve head having a stem portion disposed along a central axis and connected to the plunger end of the valve stem. The valve head can have a hollow interior portion defining interior floor and ceiling surfaces, and include ribs that extend between the interior floor and ceiling surfaces. The ribs can also extend radially around the central axis of the valve head from the stem portion to an outer circumference of the hollow interior portion. Additionally, the ribs can be configured such that a majority of an upper surface of each rib contacts the ceiling surface.