A Hemi engine is a type of internal combustion engine characterized by its hemispherical combustion chamber design. This shape allows for better airflow and more efficient combustion, which can lead to increased power and performance. Hemi engines are commonly found in high-performance vehicles, including some models from Dodge and Chrysler. The design of a Hemi engine typically features two valves per cylinder, positioned at an angle to each other, which helps improve the engine's efficiency. This configuration also allows for a more compact engine size while maintaining high power output. Hemi engines have a long history, dating back to the 1950s, and continue to be popular among car enthusiasts.