Can't get it to idle right!

The usual culprit is a vacuum leak of some kind. The engine drawing more air but less fuel will cause it to run up and down as it tries to "balance" itself. I would start with that. From there the next choice would be carb. Depending on how often and the last time it was run there could be problems with it. You'd be amazed what gas today looks like in just 6 months of sitting inside a carb.

Exactly, this plus the vacuum advance will cause it to surge. As the engine speed reduces, vacuum goes away and so does advance and the rpm drops more.. Rinse repeat.

You really need to set your initial timing properly and then modify your advance mechanism to limit total. Otherwise you'll have idle but problems at WOT or you'll have WOT but no idle..