The 2 engines are very close in design, both share intake and exhaust ports that are laterally opposed, valves sitting at an angle on top of the combustion chamber, also double rockers. Yes, the chamber on the newer engine is almond shaped. According to Chevy/Ford guys this make it not a Hemi. I guess the Gen II(426) engine isn't a Hemi either because the chamber on the exhaust side is slightly shortened so it would fit in passenger cars(not a true half-dome) lol. Also, I believe Tom Hoover had some input on the Gen III design-raised cam tunnel, twin spark plugs. Both engines are pretty damn similar in my view.