I saw that to Buzz, sure did look like a true Hemi all right.
Seems to me the basic 427 side oiler block is indeed the starting point for a SOHC. Some modifications for
oil drain back holes need to be made. It's the front timing chain cover and the heads that make it a SOHC.
The new Chrysler 'Hemi' does have the 'cross flow' design and the typical 'push rod goemetry from hell' required for such an engine.
Sal is correct in that it is NOT a 'true' Hemi. It uses a polyspherical combustion chamber design (whatever the heck that is). I speculate that the 'poly' design is to give some 'quench' to the combustion chamber, thus making the engine more compatible with lower octane fuels and not as sensitive to detonation. Detonation is and remains a problem with a true Hemi design because by it's very nature it has no 'quench'.
Hmmm, polyspherical. Is that like a 'semi hemi' with 'canted valves'? The 429-460's have canted valves.
While the Hemi design does allow for bigger valves, I still maintain it's the 'cross flow' that is the real key to it's making such good power per cubic inch.
Quench (one mans definition
): When the piston comes to the top of it's stroke and meets the head in such a way as to 'squish' the fuel\air mixture so tightly in a certain area where the gases are 'expelled' from that location at great velocity. This creates a controlled 'turbulence' and promotes more complete combustion as the gases 'swirl' around. At the prestigous "Engine Builders Master" competition getting as much 'quench' as possible is a HUGE goal because they run as high a compression ratio as they can get away with.
When I built MY engine (side oiler) I paid particular attention to this and had the custom pistons specifically designed to maximize 'quench'. Basically I changed the piston pin height to get the piston closer to the head at top of stroke while retaining a nice 'flat' portion on the piston surface where it meets the flat portion of the heads combustion chamber. You could, and people do, weld up some of the heads combustion chamber to have even MORE of a 'flat spot' for greater quench. Heres a link to my engine build thread:
427 side oiler engine build "Blog"