Mildly modified 318 PCV valve selection

I agree with RRR except for one thing
Your high idle is aggravating the TC and the only way to get it down is to pull timing, and fix the vacuum.
So if your car was in my shop, I would be doing a Leakdown test to make sure the valves were closing, on account of 298 degrees is a huge advertised spec for such a small cam. And valves not closing 100%, will cause a low-vacuum as the piston forces just-inducted mixture back up into the intake manifold. The proof IMO, is that it won't idle at 650 in N/P where it should. And if it did idle at 650, you wouldn't be having a 200rpm drop into gear.
Of course your cam timing could have something to do with that as well.