H'm off idle bog...
Could be a bunch of things.. vacuum leak, carb floats out of adjustment, not enough carb pump shot, stuck choke, fuel pressure issue, timing issue etc...
Do you know what manifold vacuum reading you are getting at idle and at idle in gear (like asked above)?
First lets look at the timing:
If you disconnect the distributor vacuum advance (that you have currently plugged into the manifold source) what is your timing at idle? Now with the advance still disconnected, what is the timing at 3000rpm?