Way way back when I was a munchkin (about 42 years ago) my Father had a 1964 Holden that had a 179Ci I-6, they had a "walking stick" breather from the Rocker Cover down the side of the engine that would vent under the car...
We fitted it with a new fangled PCV valve and hose and fuel economy took a leap not to mention the smell of oil and fumes were gone making long drives much nicer (I got car sick as a kid)..
Always makes me laugh when people "clean up" engine bays with NFI what the systems they're removing do!!
Here in Australia back in 1976 they introduced ADR27a which was emissions control on all new engines.. DISMAL Failure and it destroyed performance/economy/driveability and was something that should have been "cleaned up"
By Mid 80's car companies started to get it right, Toyota did a great job, Fast forward to today and the current crop of factory performance cars are stunning by comparison!