Plug the vacuum leak with something and leave the vacuum advance can disconnected. Mark the balancer at 36 degrees to the right of the factory mark or buy a dial back timing light. Rev the engine up till it stops advancing and set the zero on the tab to line up with the mark at 36 degrees and lock it down. Re-install the vacuum advance hose and set the idle speed. Adjust the mixture screws for best vacuum or for best idle if you do not have a gauge. Reset the idle speed if needed and repeat the mixture screw adjustment as required. Drive it!
Hope this helps.
I realy need to type this up and save it because it gets asked a few times a week. We are usualy firing up a mild to heavily modified engines here and the original specs go out the window. I probably should include a more detailed explanation as to "why" we should do it this way as well. I always found instructions without the "why" to be much less helpful.