Don,
Does your 216 have a rear main seal that would allow the inside of the engine to actually hold a vacuum? If not, a PCV system will just pull contaminants in through the rear main bearing area. That was the case on my '36 Chevy 206 engine and I had to abandon the idea of adding PCV.
If I were building the engine today I would try to adapt in a rear main seal. But when I assembled the engine 45 years ago adding PCV was not even a fantasy.
