Car Quits At Speed :( stressed

....sounds like the ignition box ....I'm thinkin that because it sounds like something that will quit working because of heat building-up and then the cool down lets it start back up again and right now I cannot think of anything else that would do that, maybe a coil but that would be a long shot, usually a coil would not act like that, they usually degrade slowly and do not come back. Maybe magnetic pickup in the distributor is another thought. (Im sure you have checked the important electrical connections)