On hot days (high 90's}while driving will start severe miss - simply shift to N, briefly turn off key then restarts normal for 3-5 minutes, then repeat (1983 AMC Concord straight 258 6, 64k miles)

Without more info, things that come to mind are vapor lock and old spark plug wires and failing fuel pump.
....Could put a wet towel around the carb and fuel lines as a test.
....A partial test of plug wires would be to open the hood while it is running at night---and you can often see the spark shorting out to any nearby metal--and especially if a particularly bad section; remember that they are carbon core which is high resistance (to lower radio interference) and the current path would rather go to metal than down the more resistive path of the spark plug)
..could pull off a connection from the fuel pump to check the pressure, though a bit hard and still keep it running without a tee....should also look for leakage around the fuel pump--often a sign that the rubber diaphragm is leaking/failing.
...all hail the memory of the Rambler..