If you think Dodge invented the HEMI, you would be wrong. It was actually invented by Augustus Herring. Better known for his aviation work- including a pre-Wright Brothers powered flight in 1899- Herring seems to have been working on an engine with hemispherical combustion chambers before 1900, and his shop at the time happened to be located within a separate factory owned by Truscott Marine. Now, it's not clear exactly how it happened, but soon after this, Truscott came out with its own engine featuring hemi heads. Who Invented The Hemi Engine? (It Wasn't Dodge)
The 'Hemi' name usage is Chrysler protected by copyright / trademark and design Chrysler patent protected. Wonder if Augustus and or others received any compensation along the way for being first or earlier than Chrysler?
The valve orientation of straight-inline-to-cross-flow intake then exhaust is quite common in Europe, though often with DOHC or SOHC valve actuation. David Vizard explored the value of similar-sized valves laid out in a fashion from directly beside each other increasingly inline to Hemi-fashion. I believe what he found is in his YouTube channel. My perception is that valve overlap for scavenging is needed less in a Hemi due to the position of the valves relative to ech other versus the flow, so the higher your RPM's climb, the more directly across from each other the valves get, and the zenith of this is the four-valve-per-cylinder layout so popular in a wide variety of engines. In effect, in the ever-more-brief time slice afforded the cylinder as RPM's climb, the one that effects the most effective scavenging and cylinder fill is the Hemi, when it comes to OHV traditional American V8's. HOWEVER, we don't actually know what craft is at work on Pro Stockers, and Chevy and Ford would never admit it if they DID have true Hemi-style cylinder heads, would they? The Dodge 'Hemi"-branded Pro Stock heads did not have a straight-across valve layout, but instead slightly canted and off-center, which I had guessed was to encourage swirl and thus greater mixture homogeneity, but who knows what actually went on with them anyhow?
