The Hemi engine, by design, does a better job of burning all the fuel in the cylinder. Also, because of its design versus a flat head, the surface area is smaller and that means less heat escapes, plus peak pressure can be higher. ... Simply put, other engine designs have gotten better over time.

What is so special about a Hemi engine?

What is so special about a Hemi engine? The Hemi engine's unique design, which features less surface area, results in less heat loss. This means the engine's peak pressure can be higher, which can result in better efficiency. Additionally, larger valves mean it's easier for air to flow through a Hemi engine.

Is a Hemi engine more powerful?

With a smaller surface area than a typical flat-head engine design, less heat is able to escape." Hemi engines produce higher peak pressure, which results in more power.