Distributor ventilation tube

Hi Guys
I’m going to modify the dizzy cap on my V12 etype to incorporate the ventilation system, due to persistent issues with moisture buildup inside the cap.
Can someone tell my what size is the tubing used on the system. I think I read 5/16th somewhere but cant find that reference again

I believe it is 5/16" ID and 7/16" OD available from McMaster Carr amongst other places.

many thanks for the quick reply.
Now to search for those plastic fittings in the cap. We don’t have the luxury of your huge supply houses down here, but I think I have located something that will do.
Regards