Points dist timing issues

[T0rch]

Hey guys. I've got a '69 Sierra grande with a 350 in it and still have the original points distributor. I've been fighting a rough, unhappy idle since I bought the truck. It idles like it has a really aggressive cam in it.

I rebuilt the carb and that helped a little, and I threw a timing light on it and tried to follow factory spec, timed initial at around 10° and 3000(ish) rpm at around 36°.

Problem is, the idle runs like sh*t unless I manually turn the distributor until it's at about 20° advance, at around which point it smooths right out. Anything past about 14° is a really hard start when it's warm, and I'm a little afraid total advance would be way up anyway. I've also noticed that the idle timing doesn't change whether the hose is connected to the vacuum advance or not... Should it? I feel like the vacuum advance should bring it from the initial 10° starting value up to around 20° or so at idle (high vacuum) to smooth out the idle.

I've also connected a vacuum gauge and it floats right between the low end of "normal" and the top end of "late ign timing" when at idle. 20° pushes it to the middle of the green "normal" range.