Right on, JTHorner. I posted a reply a while back trying to debunk the ad hype about the 'new hemi' and was met with much uninformed scepticism.
As I recall, Zora Arkus-Duntov built the first hemi head to get some hp from flathead Fords, which basically had the combustion chambers in the blocks. I think he was able to get something like 300 hp from those early engines.
Chrysler 'borrowed' the head design for their hemi engines of the 50s. As far as their 'legendary reputation' goes, the engines were mediocre in performance because the hemi head didn't allow for much compression ratio. The real strength of the engine, in my opinion, was that the low compression made it easy to supercharge, with great results. Those were hot engines, but the production versions never showed much promise.
The engine was redesigned in the mid 60s, still not much of an engine. Reliability in standard configuration was subpar, and trying to make a performer from this engine was impossible mainly because the thing had pushrods as long as your arm, and revving it one rpm above seven thousand would leave parts all up and down the street.
The 'new hemi', as it is advertsed, is a wedge design kind of twisted sideways. It is still mediocre in performance, but seems to be even less reliable than the 'legendary' engines of the past. I would stop short of calling it junk..well, maybe not... but DC's marketing plan to sell the line, especially the trucks, to the 'supermacho' guy set seems to be working. The buyers in this area seem to always have gun racks in their rear windows, and wear a lot of camouflage.
As far as head designs go, the BB Chevy is the gold standard, and some of the SB Chevy aftermarket heads, when tweaked, are as good as anything out there. The small block, coming out after the 409s, made a quantum leap-the valves were angled to be more parallel with the intake flow, avoiding a right-angle turn going into the combustion chamber.