360 driveability problem

It still sounds like a vacuum leak situation to me. While the engine is idling and warm, take off the air cleaner and if it has a choke butterfly, slowly close it and see if the idle improves. If you quickly slam the butterfly shut, the engine should very quickly die with little or no change in idle speed and quality. If it is a vacuum problem and you quickly close the butterfly, the idle may increase very notably and then die. If you find you can slowly close the butterfly partway and reach a point that smooths the idle and increases the idle speed, you have a leak. If you don't have a choke butterfly, you can use your hands or a rag.