The PCV needs to go to the plenum, yes. The problem is that he's got it dumping into just one intake runner, well after the plenum, so it's going to lean out #6 cylinder and make it misfire. I just looked at a '64 Dart the other day that had the same hookup. It started and ran poorly as a slant-5 until I clamped a Vise-Grips on the PCV hose...all the sudden it was a slant-6 again, to the owner's amazment.
I can't help but be tickled for the man, looks like he has a bunch of /6 parts there and I hope him well
