so i just put on headers and a cold air kit. im going to get it tuned at a local shop and decided to put in a ls9 cam before i get it tuned.i got all the part numbers to do the swap..so i called a friend of mine that has been a mechanic at a chevy garage for over 20 years and he says we have to pull the heads to change the cam..is he right? i never heard of that before..if not what do i tell him? could i get a Quick how to on a cam swap?