Bathtub Combustion Chamber

Also known as a hemispherical or 'hemi' combustion chamber. it has a dome shaped top or 'head' that made it more efficient than the preceding ‘flathead' design when Chrysler started producing it In 1951. Because of its dome shape. the hemi chambers valves were installed further apart than In a flathead chamber, which gave engineers more room to make them bigger. With the exception of some models from Chrysler. the hemi design Is not used except In drag and stuck ear racing.