I think the 2000 up 5.9's had a better cam than the previous ones (same as the Dakota R/T and GC 5.9 Limited cam) per Rick Ehrenberg of MA. Supposedly it's the best one to use with the keg intake. Nice mileage btw, does it have better power? Are you using the stock tune (with the death flash?)? Apparently it's supposed to be a world of difference with a proper tune in those trucks.