It has been my experience that using a catch can with a breather anywhere in the system is a waste of time. Once you add a breather you lose vacuum on the crankcase and allow unmeatered air into the system. There are several reasons why this is not a good idea. The best answer for a NA setup is to to have the pcv system tap either each valve cover, or just the valley cover (like the LS6), run to a catch can and then to the intake with a pcv valve. The trick to getting a catch can to remove the most amount of oil is to make sure you get one with the inlet closer to the bottom of the can and the outlet near the top. Another important piece of the puzzle is to get one that is baffled, or at least install steel wool. All this combines to help remove a surprising amount of oil. Now if you have gone forced induction the system needs to be a bit different but it doesn't look like many have gone that route here. I'm still not very familiar with this engine but once I get some more time with it I'll do my best to help come up with a good catch can setup, it seems to be very necessary on this engine. I don't mean to offend anyone or anything, this is just from my experience on LSX motors and rwd 3800II's. Sorry for the long winded post.