That's what the filter mesh inside the cap is for. If the breather were ducted to the clean side of the air filter, it would crap up the carburetor with oily sludge under crankcase gas reversion conditions (wide-open throttle = minimal manifold vacuum to pull crankcase gas through the PCV valve), especially with a no-longer-new engine. Ducting to the dirty side of the air cleaner means eventually the air filter will get crudded up with oil, but that's considered preferable to the other. The first couple years of cars with ducted breathers—'64-'67 California cars—came with a washable wrapper around the air filter element, but this was scrapped around '68 when ducted breathers were put on all cars; it was decided, probably correctly, that people were just throwing away and not replacing the wrappers, so pointless to spend for them in the first place, especially when air filter soakdown usually wouldn't happen until the engine had enough miles on it that Chrysler no longer had to care.
