You can add a PCV system with the valve drawing from the valve cover or the draft tube area. You need a place to draw the air from and a place for it to enter. On my 216, there is an oil filler cap on the valve cover so I made that my intake. I have a new cap with a filter there. I am using the draft tube as a place to mount my PCV valve.
The oil change interval is 3000 miles for normal driving, as mentioned in the original manual. There is no stated change with or without PCV or filter.
