Valve covers with oil cap hole

[Pike1915]

I have a question about valve covers?  From the factory do they all have oil cap holes or does it depend on model?  I have a 74 k10 350.  I was looking at new and or after market valve covers and I mostly see just the grommet hole on each cover.  I have a oil hole in one of mine.  So I didn't know if it makes a difference???  I'm stupid can someone also explain what the breather does and is for?

Thanks and sorry for my  kindergarten questions..

[LTZ C20]

All factory valve covers have an oil fill hole, a hole for the pcv valve and most should have a third hole for the breather tube that goes to the air filter housing. Most after market covers don't have an oil fill hole because they are for "show" and look cleaner with less holes. So you either fill thru one of the smaller breather/pcv holes (which are both baffled which makes filling oil a chore and slow and possibly messy) or from some other place, that in most cases is usually a fill hole in the intake manifold. Aftermarket covers are a little more money for the ones with a dedicated oil fill hole. It just all depends on what you want exactly.

[WhiteHorse75]

You are not stupid.; and your questions are not "kindergarden."
I have built a half dozen of the third generation Chevys, and I still have questions.
The guy that responded prior hit the nail on the head....form before function with aftermarket parts.
If your engine has a PCV valve (positive crankase ventilation valve), you need a port for that....the PCV valve takes positive pressurised gases from the crankcase and burns it in the intake, it also prevents your crankcase from (possibly) exploding during a backfire.....(and it turns your carburator black). In the old days, they used a "pavement pipe" which released the positive engine gasess/oil down a pipe from the valve cover to the pavement.
The other valve cover should have an oil fill hole...likely a small one, which may also act as a breather, too.

[LTZ C20]

What are your plans? Functionality or show ability? What do YOU want?