I have read,for every ten degrees of duration you add to a cam it moves the rpm (power) up 500,and for every ten degrees you subtract it moves the rpm down 500. I assume that is refering to both intake and exhaust. Also read for every four degrees you retard a cam it moves rpm up 200,and for every four degrees you advance a cam it moves rpm down 200.

Also what happens to the rpm if you go from say, ten degrees of standard split on duration to fifteen degrees of split ,and then to twenty by just adding exhaust duration? Would taking away intake duration affect the rpm the same as adding exhaust? Just trying to understand as much as I can about cams ,to me they are the most interesting part of an engine.