I gotta disagree with you on this one. When you increase compression ratio, you are not really changing how much air gets into the cylinder. The intake valves open when the piston is on the intake ******, and the gas/air mixture is "sucked" in. If you deck the heads and lower the cylinder volume, you might be changing the amount of air that can get into the cylinder by a tiny bit, but you're also getting more "****" out of that mixture by compressing it more and allowing it to push harder on the piston at ignition.
Like Ben said, it is a diminishing return, so when you get to a certain point, it's not worth going too much further. I would agree that you would gain only a little on a stock car by shaving the heads. Having said that, if I had my heads off, I'd probably have them decked a little - but I'd be real careful of the compression ratio - wouldn't want to go too much over stock. An nitrous kit is certainly gonna give you more **** for your buck.
I just noticed you are back on the forum. I don't know when you signed back on, but I am glad to see you here contributing to the board. I think everyone respects your technical abilities, even if they have other "issues" with you. I hope you'll continue to chime in when you have some knowledge to share. I'm just saying this to voice my appreciation of your input - and I hope you don't stop sharing your knowledge and leave the board if people start to give you grief over past incidents.