Classic/Antique Car Repair: cooling system, small block chevy, 4 quarts

Question
After rebuilding a 1966 small block chevy, we put what we could in the cooling system (8 quarts of antifreeze and 4 quarts of water) and the temperature gauge went to it's highest point rather quickly, but there were no leaks or fluids coming from the overflow. Thinking old school, am I right to think it may have vapor locked, trapping air in the heater core or elsewhere? If so, what's the easiest way to bleed the air (the thermostat housing does not have a leader plug like some of the newer models)?

Answer
Hi Steven:
Vapor Lock is caused by heated fuel in the fuel line, which would make the care hard to start after the fuel in the line vaporize.

Your problem maybe either the thermostat or the water pump. The thermostat should open at around 190 to 210 degrees. If this is not happening, that is your problem. Also, antifreeze must flow through the engine at the water pump. If the water pump is not working, that would cause your problem. You will have to test this by removing the top hose from the radiator. Once the engine is hot, antifreeze should pour from the hose when the thermostat opens. If not, either the water pump is not pumping (bad) or the thermostat is not opening (bad). Next, remove the thermostat first and re-test. Without a thermostat, the water pump should push antifreeze out of the top hose immediately. If not, you've got a bad water pump.