I run the old Direct Connection mechanical carbs too. Absolutely love them. Motor idles around 7" of vacuum. The stock Mopar specific PCV works fine in mine. No fast idle issues at all.
Maybe it's something else? You can make a flow restriction plug and stuff it in your PCV line. Drill a smaller hole in it to reduce the air flow. I did that on my old slant 6, and it worked perfectly.
1970 Plymouth 'Cuda #'s 440-6(block in storage)currently 493" 6 pack, Shaker, 5 speed Passon, 4.10's
1968 Plymouth Barracuda Convertible 408 Magnum EFI with 4 speed automatic overdrive, 3800 stall lock-up converter and 4.30's (closest thing to an automatic 5 speed going)
| 
