Quick Oil Catch-Can question

[asshanson]

You can use a single catch can with three ports no problem. I modified his drawing and added the top line going to the intake. You still only need two check valves because the intake pipe will always be vacuum. And even if it wasn't, no big deal because there are check valves only allowing air out of the valve cover and into the intake pipe.

This design also allows the valve cover to breathe out of two ports under boost, not just the side port. I drew green and red arrows to show the only allowed direction of airflow.