manifold vaccum for vaccum advance ?'s

Look; un hook it. Figure what initial timing the engine wants. Period. Then rev it, see what total advance is. Then do into dist, and modify it. Period. The whole time, lowering the idle screw. Those idle mixture screws don;t do crap, until the timing is correct. No ping? good.

then hook up the vac ; think about this- under throttle, there is no vacuum to make anything work.

If the timing advances at idle, with vac; other issues. Like carb . What is idle vac? what is power valve ? what are metering rods and jets?

Start with timing first.