When it runs hot, it will not go in reverse

Question: I have a 1983 Ford Econoline box truck with a 351. I have changed the water pump, spark plugs, oil change, thermostat and exhaust system. The muffler pipe was turning orange before I changed it. But the engine is still running hot. When it runs hot, it will not go in reverse. Could you tell me what else I could do about it running hot? Already Tried: water pump, spark plugs, oil change, radiator flush, changed exhaust system Answer: 1) Have your ignition timing set/adjusted (should make a huge difference) Excessive ignition timing will cause an engine to run hot and can make the exhaust glow red/orange 2) Check/Replace the clutch on the clutch fan(common) or install an electric fan