Do you ever run into people who say that your engine is not a true HEMI? If you do, here is your response: What makes a HEMI is the design of the head, which is not a wedge head like everything else. If you compare a HEMI and an LS head, you will see how much better it is. A HEMI has two canted valves that open into the cylinder and uses a centralized spark plug. Modern HEMIs (5.7, 6.1, 6.2 and 6.4) have this design, but use two spark plugs for better burning of the fuel and less emissions. You have to realize that an engine's design will evolve over time to obtain better fuel efficiency, fuel economy, power, etc. That's just the way it is. The HEMI engine is no different. It is not identical, in every detail, to the HEMIs that were in Mopars back the late 60s/early 70s. But, the HEMI engine that is in our Challengers is, in fact, a "real HEMI" because it is a direct descendant from that old HEMI design and the one currently being produced. Dodge has just made very wise improvements to it over the years and has done a remarkable job of marketing and producing these fantastic engines. They have all the positive traits of a real hemi (valve size, port flow, flow quality, burn time/efficiency) with far fewer of its problems. Anyone who owns one should be proud.
“HEMI” is short for Hemispherical Combustion Chambers. Which is what these engines have, as opposed to the wedge shape used by most Ford and Chevy engines. The original Hemi was the Desoto “Fire-Dome” V-8, which if I remember was a 331 c.i.d. The one obvious unique feature of the Chrysler hemis is the spark plug wires going through the center of the valve covers. No other engine has this.
This article provides a pretty good description of the hemispherical /semi hemispherical head design. https://www.motortrend.com/how-to/hemi-engine-pros-cons/
