im late to seeing this thread & it looks like you got the PCV thing figured out... but i wanted to point out that your air cleaner pictured above does not look like a 79 403 olds air cleaner, it has very different markings & features compared to other 79 403 t/a air cleaners ive had or seen, even the link you posted to "chicago musclecar parts" shows a different air cleaner base. unless they made 2 different versions, yours is close but there are numerous differences to a 79 403 base. heres a link to another one that has very good pics, some at the same angles as yours & you can see they are not the same.
just wanted to point that out before you try & sell it as a 79 403 t/a air cleaner.
https://www.ebay.com/itm/1977-1979-T...4AAOSwahhee~sE