The carburetor may still be set too rich, but it is certainly not too lean. A lean engine would stumble and/or die if the PCV line were removed from the back of the carb. With the PCV valve removed from the valve cover, it is possible to see an rpm rise on a properly tuned engine, as the difference between crankcase gases and atmosphere is significant. Better-quality air from the real world will cause the engine to breathe better, raising rpm. I have seen a vacuum leak on the PCV or brake booster line raise idle speed by as much as 1300 rpm.
