[rotorwrench]

Could be a starter problem. Broken or cracked wires like to separate when hot. I would also pull the distributor and do some inspection & service with the flyweights to make sure the spark is retarding all the way for starting. If a person cranks the starter with the ignition off, it would let you know if it's trying to kick back or not. If it still won't turn over then it's time to start checking all the starter system components. A bad relay, a bad starter cable, or any problem with battery or its connecting cables could also cause starting problems. Stuff wears out and when it does, it starts telling you there is a problem. Check the easiest things first.