If I was inclined to add PCV to my truck, I would put the PCV valve in the top of the valve cover, maybe in a hole drilled in to the stock oil cap.
I would then find a draft tube from an older model 216 or 235 which had the oil cap on top of the stand pipe. I would then put a vented cap there.
Why?
1) No issue with sucking oil out of the crankcase, or having to do anything to the stock draft tube except for plugging the hole in the bottom end of the down pipe.
2) Having the PCV valve at the top of the valve cover will scavenge the volatile fumes and steam which tend to collect on the underside of the valve cover with no way to get out unless there are multiple slots in the top of the valve cover. (The original slotted valve cover allowed these fume to escape while the vehicle was not in motion. These slots were an integral part of the crankcase ventilation system over and above merely being holes for fresh air to enter as blow-by contaminants were being sucked out via the road draft tube.)
