After reading three pages I have to ask if anyone knows how many cubes the SBC guys are running. A 318 would be at a loss against a 350 let alone the popular 383 stroker that they build. If your class has no displacement rule it seems that cubes would be the way to go. As stated before the lower rpm and broad torque curve would trump high rpms. Power at all engine speeds is a basic function of how much a/f you can stuff into the engine. A four inch 360 will make your 450HP all day at 5500/6000 rpm. A 273 would make it also with a lot of flow and 10k rpm. The small block can be made to live that high but why do it if you have no cid rules? As a drag racer from days gone by I found it more to my liking to build a Mopar and run it 2-3 years than build a SBC and tear it every week to replace valve springs and check for other rpm related ailments. I'd take a long stroke flat torque curve over a peaky screamer. Listen to the nascar boys on sunday. They sound like the Indy cars from the 60's turning 9500 rpm. If you could find a clip from the early 60's of nascar all you would hear was thunder.
I'll take the thunder.