Breather hose on the rocker

Good morning all, good weekends? 

After nearly giving up on the car due to a garage taking forever she's backkkkk and smiling all the way Home driving her just reminded me why I love her. 

Just a quickie, switched to a Weber carb so now need to grab a filter for the breather off the rocker cover. Any idea what the pipe size is so I can order one? I guess I could measure it but that would be too easy. 

Also oil light flickering on idle, it's not knocking so don't think it's the pump, but the oil pressure switch looks new as well. Mechanic thinks when previous owner last serviced it may have put to thin an oil in? 

Really want to avoid taking it to a garage to yank the sump off. 

Happy Monday! 

change the vis of the oil from 10w30 to 10w40 or 20w50..(which is what I use) and a good filter not a FRAM, Bosch, Store Brand, or Gene Eric.

I would have to measure mine, so it is easier for you to take yours off.

Thanks Briano1234 going to try that as first point of call!