2000 Dodge Dakota cooling system

My truck was overheating, I didn't push the issue. I stopped, let it cool fill it up and went. This was one trip that took four stops and fill ups to get back home (10) miles. I have since replaced the water pump that had gone bad. Problem persisted with the overheating. Replaced the thermostat, problem remains. Flushed radiator with hose, water flows freely; tried the same with block with no flow although I am not sure that works (water pump probably doesn't allow that.) The overheating is accompanied by all of the water being forced into the overflow and spit out of the truck completely. I am mechanically inclined, it just for whatever reason I have always hated working on vehicles, therefore I don't have the necessary knowledge. Any info that leads to a solution for me would be heaven sent through you good people. Thank you very much. Stephen Cochran