Valve cover breather

What exacly does a valve cover breather do? and where on the valve cover would you install it on a 420a? Cause ive seen those at like pepboys and auto zone those little mini looking intake filter things and i was wondering what those valve cover breathers were for?

im pretty sure it goes on in replacment of the hose that goes from your valve cover to your intake.. i had one on my car for five minutes... i have a front strut tower brace so the breather sat against it and over 2k it just made the worst viration noise eva... i dont see its point so i just put the lil tube back on

All it does is keep your intake alitter cleaner, It doesnt really add any power. If you turbo charge it you will have to use one though.

humm.... search around.. there're tons of thread on this forum that already covered that topic. i remember one of my threads under "i painted my valve cover" has a pic of the breather installed. don't go out and buy those fancy special breather kit. they're wast of money. all you need is go to autozone and buy a oil filter can.. the cheapest one'll do that job well.

all they do is equalize the pressure