Why?.....It's a cam-in-cam design just like the gen IV I'm sure. This ain't no oldschool bumpstick like in your 1971 small block Chevy. With a variable cam design, the "specs" change as your driving it. (lobe separation anyway) PCM controls it as it sees fit for the particular driving conditions, for better emission control, and smoother/broader power curve. So the "numbers" that you're used to seeing in Hot Rod magazine/speed catalogs/performance cam sheets or whatever, are meaningless when entering the world of the gen IV or V VIPER!