PCV or Breather caps???

Glad you got it in OP; a wise move. Now.... did the engine's idle change and need significant re-adjustment after the PCV was put in? Is there any new hesitation when you first lightly open the throttle? And have you measured the vacuum in the intake at idle?

The reason to ask is that ALL PCV's are dual flow units. There is a low flow level for when the engine is at idle and other low engine airflow situations like mild cruising and tooling around town, and a high flow level for heavy cruising, going up hills, WOT, etc. These 2 flow levels generally reflect the load on the engine, and the trigger for the PCV valve to change from low to high flow level is the vacuum level under the carb, in the intake manifold. If you have a cam that idles rough, generally the idle vacuum level will be low, and stock type PCV valve will open up to the high flow level at idle. That will throw off carb adjustments in the areas discussed in post #4.

In that case, you don't want a stock PCV but one that has the flow level transition at a lower manifold vacuum level. You can find some from the parts stores, as suggested in post #12, or use an adjustable one; and MP has one for stock valve covers. I can't find any info on the one you have as for the transition vacuum level.

So if the engine's idle and off-idle throttle response has changed for the worse, then you may have some further measurements and adjustments to make.