I agree that cam has to do something with adding compression, air elasticity and all that. I tuned a six-pak '73 Dart Sport 340 for a friend that bought it, and supposedly was a "built" engine. The car would beat my 440 'Cuda and a lot of others. It was real loud though, had headers and those see-through mufflers. The point: after we tore it down...8.5:1 compression - bone stock, 360 heads, 3.23 posi, and a shift kit! It had 9 or 10" at idle and timed at 12BTC, but that was on 1980's gasoline. The friend still wants the same combo to this day...for his kids. That cam rocks a smallblock.