I believe my 250's had at least a 3/4" hose running from the valve cover to the air cleaner. Drilling a hole in the 2nd PVC might not be enough of a vent. After it's warmed up and idling take the PVC's out of the valve cover and checked to see how much fumes you have coming out. It's to early in the break in process to tell anything but for piece of mind I would do a compression check and write down the test numbers per cylinder. At least you would have starting point as you go thru the break in process.
