Dodge 440 ,miss firing

First, an isolator that is shorting out, can cause the engine to miss, or die completely, because it can short all power from the ignition system. Most performance problems are electrical. If you do not have a VOM, you should get one. If you know diesels, then working on a gas is not too much different. Instead of the heat of compression igniting the fuel, a spark is required in a gas engine, that is the purpose of an ignition system. If carb is empty after running, check all the rubber connections between the tank and the fuel pump. These develop cracks and leak air in, stopping the fuel flow. You are getting some pretty good advice, maybe just starting over, and verifying everything is working as it should, before moving to the next phase, including the isolator block. Then start on the fuel system. I would recommend filling the carb through the overflow vent tubes, with a turkey baster filled with fuel. If it then runs until it is out of fuel, start checking the fuel line from carb to the fuel tank. This is mundane but must be done to find the actual problem(s).