Not too bad, but the first generation Hemi's (Firepower 331-392) were actually based on a new engine design. The second generation Hemi (426)was really based on the 440 engine block with slight mods ( cross bolted mains and additional thread bosses for the Hemi heads). The Combustion chambers were angled to narrow the engine dimensions so it would fit into the B-body engine compartments. The 1st generation was had more of a true hemispherical combustion chamber than the 2nd due to the fact there was more compartment space so no compromise had to be made.
Yes.....he didn't go into every facet of the Hemi development. But, it was a refreshing POV from a guy that tuned European exotics for 40 years and landed into the best American muscle car of all time!!!