Dodge Repair Questions? Ask a Mechanic for Answers ASAP
The only place you could get enough of that built up to overheat that quickly is in the radiator and you already changed that.
If you think you have a circulation problem, then remove the thermostat and put the housing back on. Leave the upper hose off the radiator and put a hose in the radiator cap and run the engine to see just how much it pumps out of the hose.
The only things left to completely stop flow would be the thermostat, whether it be defective or in backwards or the impellers rusted off the water pump but that is rare.