Just needing some help

I inherited a 1969 dodge charger from my grandfather. He bought it new, and had it worked on several times. I believe he said it was rebuilt twice. Last rebuild was because previous mechanic left shop rag in distributor hole when he installed the new distributor. Anyway, the car runs very rough. I can adjust the timing and get it to idle smoothly at 950 rpm, but when I reconnect vacuum advance it jumps to 2300. What am I doing wrong? (I'm just a farmhand with general knowledge of mechanics and keep it running smarts) My main love is the animals, but I don't want to throw away a good vehicle if I can fix it.