Classic/Antique Car Repair: 1956 chevy 210 delray, flex hose, timeing

Question
my car run strong in the beginning, as soon as the car gets hot it starts to loose power,the engine does not overheat and the timeing is right on.i am afraid a wire or the coil might be getting to hot. what wire might cause this or whst else could be the problem?

Answer
Benny;
HI I would flush the rad. and change the thermostat. also check the upper hose , as some times if it is not a flex hose or if it has no spring on it, it can suck itself closed when running and make the engine run hot. also are the plug wires good and away from the motor.