Slant 6 pcv valve rattling issue

Sure there are many different PN's w/ design differences, but I doubt all these PN's will be available forever (or even now), so we need options. I recall seeing "universal" PCV valves in the HELP bubble packs at auto parts. SSD agrees that there is a designed-in "minimum flow" (i.e. controlled vacuum leak) at idle, and that is most likely the critical difference between them. Presumably, one must tweak the idle mixture of the carburetor to match the extra air flow. Ideally, the carburetor will be tuned to account for the PCV flow at every manifold vacuum. With today's after-market O2 sensors (wideband are best), you can monitor such things. Those who install fuel injection systems w/ O2 feedback have automatic compensation for any PCV flows.