yep, I understand your point very well. The issue that you have is that you're saying maximum possible intake flow is not dictated only by CID (lets leave ports, valves and cam etc out of this and assume they're all optimized for the application) but also RPM. That I agree with. If you have a 500 CID motor that can only turn 3500 RPM and a 350 that can turn 7500, you'll have your day with the 350, assuming, again, that other variables don't hinder you (traction etc etc).
I definitely don't think you're blowing smoke, I just think perhaps I never communicated my opinion/point as well as I wanted to! I respect your opinion, Royce.
I also have an issue with the term "maxed out." Holding CID constant (say 377 and 400) you would have to arbitrarily dictate an RPM point at which you would say that each motor, as defined probably by aftermarket availability, is "maxed out." I personally know a guy who has a 434 stroker smallblock who's setup is built to 7400 RPM with a stock block (see 1BAD80). 400's can spin if you spend the money on them.
So what this whole issue comes down to is this: does the shorter stroke and over-square characteristic of the 377 reduce the stress on the internals (piston acceleration/velocity) to a degree that in any situation it is more practical to build than a 400 in terms of the maximum airflow each motor can produce at its maximum "safe" RPM as defined by a parts setup that costs the same for each motor? My point is that I don't think so, and I also don't think that a stock 350 chevy will spin 6500 RPM. Not for long anyway. Furthermore, as I mentioned earlier, the slugs on the end of those rods are heavier than the original 350 slugs, because they're bigger. Lastly, even if you do think you can make a few passes at 6500, is it really practial to stretch those stock parts right to their limit, hoping that you never ever miss a shift and stick it to 6800 one time? I just think its a lot to bank on...
ANyway, fun discussion. Good points-