As a mechanical engineer I applaud you for an outstanding article Mr. Sherman! The detailed and technical descriptions, particularly of the original engine design, aided by the high quality images reminds me of the sorts of articles I'd read in print magazines of three decades ago. If memory serves, your writing contributed to the automotive media of that era also. I'm happy to have rediscovered you.
Thanks lack of sharp edges allowing higher compression makes perfect sense to me, I'd never considered that! But I question "flow through design": for a good portion of the cycle both valves are closed halting all flow. I understand there's tremendous turbulence and an explosion but there can't be any inertia toward any particular exhaust route. I'm still imagining phenomenal gains by unshrouding the valves, even if that were the only improvement. Not trying to be argumentative, I deeply enjoy these discussions.
Gee whiz my 1976 Toyota Corolla with the 1.6 Litre was a hemi. Lots of cars have hemis. Check out the 2.5 litre V8 Jaguar/Daimler engine. It looks just like a Chrysler product but for sure they would not be allowed to say, “Yeah , it’s got a Hemi”. With the Chrysler engine, it is just big.
It really is the most efficient head design for combustion, just seems like Detroit has something against the OHCs that complete the package. Ford's 427 "cammer" (their 616 HP answer to the Mopar 426 - developed in 90 days!) is the notable exception. 🙂