I have a 67 Charger 383 HP and it keeps overheating. I have flushed the radiator with Prestone radiator flush, changed out my thermostat to a new 180 and then again to a 160, pulled the pump and is fine, and checked the hoses for blockage. Thinking now that maybe my radiator needs to be replaced or redone. Reason: I was reading the 67 manual and it says the 383 is suppose to take 17 qts of coolant (4 gallons+)...??? is this correct? When I have drained the radiator I only get about 2 gallons of coolant. Any ideas anyone?