oil filler cap in performance valve covers??

[Heveyb]

OK, I'm feeling a little stupid asking this question but I just bought some new Chevy Performance valve covers to replace my leaking tin ones that came with my crate 350. They each have a hole in them, one for the PCV and on the other one for the breather. there is no oil fill and cap like on the OEM covers. Is the deal to use the breather hole for the oil fill as well? As I said, it may be a stupid question, but then again everybody on here is always willing to answer questions without too much humiliation!! Thanks