440 tuning troubles

You need to rebuild the carb from the sound of it. I like the AED aftermarket kits with the reusable nylon bowl washers, float adjustment washers, and gaskets. I would also invest in the vacuum pod spring assortment, as I think the secondaries are opening too early. Also, I think the spec on the acc pump lever is .010, but I adjust so there is no play at your final idle speed setting. Also verify (pull them off and look) that all your spark plug wires are intact and not burnt at the boots.