Right Amount Of Coolant

[RICK LAKE]

AR_Cobra DJ It's not a head gasket problem. You said the thermostat opens easier than the new open. Do the boiling water test on the stove, (when the other half is not around). Heat the water and watch the temp of it. See at what temp the themostat opens. If the spring is weak it could open at 160F. Issue with this is the motor doesn't get enough heat in it. New stat will fix this, the temps may read higher but as long as it doesn't go over 200F you are not going to hurt anything. You should see a 10-20f degree down when the new thermostat opens on the temp gauge. It will close and open a couple of times until it balances out the motor temp. After that it should be steady. Hard driving or long idles will raise the temps slowly but driving at over 30 mph will bring them down again.
Heater core lines, leave them hooked up but check for flow on them with heat going in one side and the other side a little cooler. Your gun should be able to check this. Listen or feel the hole for any wierd or funny noises. This could be air stuck in the system and causing the coolant level issues. This is why it might be worth the money to have a place vacuum the system down and fill. Try the other things first and check thermo. Good luck. Rick L. Ps more side notes Does your radiator stand straight up and down in the nose of the car or is it at an angle like ERAs? Straight up no changes on angle, ERA installs a splitter to help get more air to the top of the radiator. I run those 2 small fans in the frontend and look cool but block air to the radiator. Splitter works better for racing. The other thing is Aluminum or Copper? I went from Copper to Aluminum for weight in the nose of the car. Saved 20 pounds, Almost Some of the pro's can tell you which one works better in heat removal of the coolant. Later