You don't have to take the heads off for a cam. You do have to take the radiator and steering rack out



http://www.ls1howto.com/



If your're after big HP over stock, a simple cam swap isnt going to do it. The stock LS6 cam is pretty aggressive as it is. You might make an additional 40rwhp with a seriously aggressive cam. Now if you throw in AFR heads, ported throttle body, and an agressive cam, you might get somewhere.





Or you could just put a procharger on it and make 550rwhp without even taking the valve covers off