Chrysler’s Hemi engine, known for its hemispherical combustion chamber design, first roared into life in 1951 as the “FirePower” and hasn’t lost its spark since. Though not unique, the Hemi’s design, resembling an over-enthusiastic bowl, boasts efficient airflow, boosting horsepower but occasionally coughing up unburnt gases like an old man with a cigar. Originally an experimental military marvel, the Hemi keeps revving high with its distinctive wide valve covers and a penchant for high-octane fuel.