In that case I'd start by pulling the hood and going for a drive. Alternately you could try grabbing some bags of ice and tucking them around the carb, then going for a good drive. If the ice is still there when the engine is hot and it normally acts up, you know your problem is in the carb bowls. In which case you can get a spacer as mentioned earlier, or you can make up some sort of insulation system to help isolate the carb from the engine better.