Oil in air filter housing.

I recently took the air filter off to adjust the choke and idle, and discovered oil in the air filter housing. I know that this could possibly be indicative of other problems, however noticed an "OIL LEVEL" stamp in the bottom of the air filter housing. Before I assume that I have worn piston rings I wanted to ask, is there supposed to be oil in the bottom of the housing? Please pardon me if this is the world's dumbest question, but before I start pricing out engine rebuilds I have to ask.

I have a '65 with the 273 V8. Any advice is greatly appreciated.

Thats an oil bath air cleaner,,,,,the idea was that the dirt in the air thats going into the carburetor gets trapped in the oil and it needs changing,,,,,,,people sure like to convert it over to the modern type,,,,,,,,,as for your engine condition, if you feel pressure blowing out of the oil filler cap hole, that
is a warn engine,,,,,,

donivan65 wrote:Thats an oil bath air cleaner,,,,,the idea was that the dirt in the air thats going into the carburetor gets trapped in the oil and it needs changing,,,,,,,people sure like to convert it over to the modern type,,,,,,,,,as for your engine condition, if you feel pressure blowing out of the oil filler cap hole, that
is a warn engine,,,,,,

Hopefully that is good news. I appreciate the explanation and help!

Thats what we come here for,,,,,,,to keep these vans going,,,,,,,and to help people do it,,,,,,,,

I wonder if someone swapped that into the van.
Here's an intro film for the A-100s, note at 2:20 it shows a typical paper filter housing.
https://www.youtube.com/watch?v=kcewnrO5vIc
and pt.2
https://www.youtube.com/watch?v=F3J-KeyDRZU

It takes about a quart

I swapped mine out for a standard paper filter air cleaner off of a '70 318