How big is your cam? If it has a lot of overlap and low vacuum at idle the throttle blades may be open too far like was said already. This causes the transfer slot to be over exposed and the engine will try to idle off the transition and idle circuits and this can cause nozzle drip. Adding initial timing and/or hooking the vacuum advance to a manifold vacuum source can help this.
If the cam/ignition timing isn't causing it I'd be inclined to think the float level was too high, the float was damaged or the needle/seat assembly was bad. I'd want to take it apart and see what I could find and you'll need a kit to put it back together. That's all you should need unless the float is bad.