[Baron Von Zeppelin]

Originally Posted by alsalp

The first picture is borrowed from the web. These are of my own air cleaner.

The first picture you posted - borrowed from the web - has the 5/8" hole in the rear.
That isn't factory.
Someone must have had heavy blow-by and plumbed it into the driver valve cover or crankcase to eat off more of the smoke.
(guessing)

trivial factoid

[alsalp]

Originally Posted by OG68

For the carburetor fuel bowl vent. 70 (California) and 71 cars

Like this?

[Baron Von Zeppelin]

Originally Posted by alsalp

Like this?

Yes