Need input on crankcase evacuation remedies

[Vegas69]

I ran -12's from the top of both valve covers to separate catch cans. I ran the snot out of mine everywhere and they worked very well. They would smoke a little until the moisture burned off. I don't recall any messes. I would drain them once in a while. Never more than an ounce or two.

Why suck the vapors back in the engine? I get it on a street car where you want to go 3000 miles between oil changes.