depends on how juicy you plan on making the truck 30# is good for stock to mild, i can peg my 30# gauge at 2700-2800 rpm in the higher gears, i dyno'd 248hp with a bad lift pump a year is so ago i have since gone to a straight exhaust and moved the cam plate full forward, i figure i am maybe 275-300hp, 50# should cover most truck mods, significantly more then that and you are getting into big time mods