I know that when I spoke with the guys that sell the 383 kit, they told me to leave the stock cam in if I want to maximize the low end grunt and I am not worried about higher RPM power. I figuire this truck will mostly see use on the highway at about 3K RPM and when its pulling thru the gears at half throttle it should be shifting at about 3500-4000 with a load on it. There is nothing to gain by me camming it to make power as if it were in a car that was going to be hot-rodded, its just a matter of what the intended use is. One thing I did notice, the cams we are talking about are listed as Hyd-Roller grinds and this is a Hyd-Flat Tappet engine. I need to call Crane and talk to them boys to see what they recomend. I'll let you know.