Stop in for a cup of coffee

71GSSDemon said
So for grins, I checked the spark plugs. 2 were a bit wet, the rest a nice caramel color. The last drive was just about 4 miles and a few WOT stomps. I know it should be much more controlled than that, but it does tell me it isn't stupid lean. Also, I have the light silver and light blue springs and black stops. Chart says 18⁰ mechanical added to my initial 18⁰ and all in at about 2000. Maybe the manifold vacuum advance was part of it. So both rich and timing?

First, the charts may or may not be worth the paper they are printed on.
When a few have been verified then you can have some confidence the others may also be correct.

Using the chart with the 18* initial, my understanding is that was at 1000 rpm.
Lets look where that falls on the chart

So its telling us that at 1000 rpm the advance has moved out 2.5*
Looking at the Black bushing, that supposedly stops the advance at 17.5* advance, so 15* more.
It also indicates that will occur just above 2000 rpm which maches pretty close to the measurement you mentioned in the first PM.

So far the chart seems pretty close to your measurements. So that's good.