Overflowing, bubbling coolant out the reservoir has always been a stuck thermostat for me. Even the Motocrafts do this when they start to go bad.
Just because a thermostat is new doesn't mean it's good. They can be faulty and not open properly. You can also ruin a working one by overheating it and destroying the wax that controls it. This is what usually happens when you put a new one in but don't 'burp' the system and purge all of the air by following the procedure for refilling, then running the engine with the cap on loose, letting the engine cool, then refilling.
You need to start over, replace the thermostat, fill with coolant, put the cap on but only tighten it to the first click so it's loose and air can escape, then run the engine until the temp needle goes up to the middle, and goes down, showing the thermostat has opened. Turn the engine off, let it cool down completely, then fill the radiator and top off the reservior. Run the engine again, let it cool, and then top off the reservior and it should be good from there.
If you don't do this and just fill it up and take off, you can usually expect more overheating and ruining a lot of thermostats, and likely the engine too, if you haven't already. Hopefully you shut it off before it ever got the chance to overheat to damaging temperatures. If not, maybe just the head gaskets will be blown.
