MrZO6,
I'm not a really good person to answer those questions, I'm not really a cam expert, just have a good understanding of the theory and mechanicals involved.
I'll take a stab at it though, and I'm sure somebody will correct me if I'm off base.
The lope you mentioned is probably the overlapping of duration between the closing of the exhaust and the opening of the intake. The dynamics going on in the compustion chamber are such that as the exhaust gases exit, the intake valve is opening, the exiting gases actually produce a lowered pressure condition inside the cylinder that helps draw the intake charge into the cylinder, while the exhaust manifold or headers help draw the exhaust gases out.
I may have answered your next two questions by answering your first... not sure.
But on the emmissions part, I would venture to guess that is taken care of by utilizing the computer to control the timing of spark, fuel, and amount of fuel or fuel/air ratio.
The O2 sensors downstream in the exhaust, and the MAF in the ari intake path collect information and feed that to the ECM, which in turn controls the timing and varies the air/fuel mixture many times / second. Since this is real time information that changes as needed to produce the most efficient burn, I'm sure that's how we can get so much HP and still meet emmissions requirements.
That is something we couldn't do before computerized ECMs came along. On carb. engines the best that could be achieved was to jet the carb for average conditions, and accept the less than efficient results when the conditions were not "average" as the system was originally set for.
Did that come close to what you were looking for?
Stan