Need Some Help

I have a 68 Charger with a 440. The car starts up fine and idles fine if you just let it sit. But if you quickly tap the throttle, and rev it a little, it hesitates. If you hit the throttle slower, but rev it higher, the idle jumps up real high and stays there. Does anyone know why that is? Any help would be appreciated. Also, I put a hand vacuum pump on the vacuum advance and pumped it. After the vacuum went up, it would quickly bleed off. I was wondering if that was normal because the vacuum advance on the 383 that I have does the same thing.