This is more of a general question, or maybe an observation on the factory Tune-Up specs. I've noticed that many if not most engines seem to "like" a bit higher RPM? The Y-Block factory spec was 475-500. Does that seem a little bit low, do you tend to set the idle RPM higher on your Y Block?

A well tuned factory cammed engine in good shape "should" idle smoothly down low without complaint. Doesn't mean it needs to remain there, but it is actually a kind of diagnostic I suppose. In that sense it is pretty common to see people try and compensate for different engine derangements by ramping up the idle speed.

The reason I ask is I've been going through the 2100 carburetor on my Y and discovered that the throttle rod and throttle arm itself wasn't staked or secured properly, at some point in its life bushings were installed to clean up a vacuum leak. But whoever reassembled it, the result was quite a bit of slop in the movement to open and close the throttle blades. The butterflies seem to fit the bores very well, but in the past it was difficult to achieve a consistent factory idle down low, even for test purposes and I kind of gave up. At 600 or so it idles absolutely smooth. Having made what I think is a lasting repair to the throttle assembly I'm interested how it will turn out when things warm up a bit.