An engine design where the top of the combustion chamber is shaped like a half-sphere, allowing for larger valves and a straighter path for airflow. This setup yields excellent volumetric efficiency and high power output. While originally a descriptive engineering term, it is universally recognized as the trademarked name for Chrysler's legendary high-performance V8s, even though newer iterations use a flatter chamber design.
Heard on the job
That old Charger sounds mean, does it have a Hemi in it?
Insider tip
True classic Hemis are massive and heavy, making them highly sought after by hot rodders despite their physical footprint.