[gr8scott51]

How hot is it outside? Quite often, older, carburated enigines will vapor lock (gas flashes before it gets to the carb). Often, after letting the engine cool, the problem goes away and the engine will start again. Make sure your gas lines aren't too close to your headers and not contacting your engine or other heat source. You can even wrap them in foil to prevent some heat transfer. Just a possibility.