The current-production "HEMI" engine heads are flatter and more complex than the 1950s–'70s Hemi V8 chamber. The combustion chambers are no longer truly hemisph

The current-production "HEMI" engine heads are flatter and more complex than the 1950s–'70s Hemi V8 chamber. The combustion chambers are no longer truly hemispherical. It uses a coil-on-plug distributor-less ignition system and two spark plugs per cylinder to shorten flame travel leading to more consistent combustion and reduced emissions. https://en.wikipedia.org/wiki/Chrysler_Hemi_engine#Third_generation:_2003-present https://en.wikipedia.org/wiki/Chrysler_Hemi_engine#Third_gen... As the engineering involved in new engines has improved and evolved, the true hemispherical chamber has morphed and twisted into more sophisticated and complex designs that are meant to extract more power, with lower emissions, from any given combustion event. https://en.wikipedia.org/wiki/Hemispherical_combustion_chamber#Design_evolution_in_modern_engines https://en.wikipedia.org/wiki/Hemispherical_combustion_chamb...