Say your standing in front of a 305 V8 Firebird, the right cover has 2 holes, one is the cap the other is a tube comming out connecting underneath the carb. What is this? Whats its purpose? Do I need it?

Not to confuse with the left side where another tube comes out but connects to the air filter.

With this one, I saw Edlebrock makes a decent valve cover, I was gonna replace both and instead of the tube on the left side I was gonna put a push down filter (because it looks way better lol) but the otherside im just not sure what it does.

Thanks

 

It is your PCV valve.

It helps keep moisture and exhaust gases purged from the oil, so that it stays clean and doesn't turn to an acid.

Yes you need it.

Those breathers only "look" "better" if you think a slimy mess of oil sludge on top of your VC "looks" "good". And of course, it helps if you enjoy that smell that old cars always have; old oil vapors, exhaust, etc., and that wonderful film of oil all over the entire car, inside and out, top to bottom, front to back, that comes from having oil mist constantly spewing out of the engine.

 

Most aftermarket valve covers don't have an oil fill hole - which is fine, you fill in either of the smaller holes.

Most have a PCV sized hole in each cover. Connect your PCV to one cover, and a breather in the other cover. Then the PCV pulls vacuum, fresh air enters the breather side and the bad gases get sucked out through the PCV.

 

lol okay I get the right side hose, kinda why I asked since I was not very sure.

But the left side hose that connects to the air filter ontop of the carb, well whats the difference form using that filter or the push down one? Nothing comes out since its only pulling air in right? I I could use one of the push filters (a second) under the hood right? No harm done?