First is how do i go about picking the right cam? Also If i wanna change over to a 6.0 liter in my truck should i just get a 6.0 liter short block and swap my top end on it, or a whole 6.0 liter enigne? and go from scratch with heads and cam?

 

I would get the short block and put a set of heads and a cam on/in it.

 

Read all you can about cams, look at others running cams and the results they gained.
One thing you need to start with is to decide what or where you want the engine to perform. Gains at the top are usually at the cost of low end loss. How high of a stall are you goin to want to run?

 

You need to decide exactly how high you are going to rev your engine and where you want to shift at then pick a cam with an appropiate power band. There isn't a 'magic' cam yet so you are going to have to sacrifice a little power in either the upper or lower power band. Make sure that you get a TC that is well matched to whatever cam you decide.

P.S. The search function is your best friend...

 

between 3000 and 3200