Overheating issues

Unless you want to remove the radiator again & have it rodded it out....read what follows.
The rubbish that was in the rad came from the engine.....not the rad. So there will still be rubbish inside the engine. You will never get rid of it by flushing with a hose. At higher rpms that stuff will be dislodged....& will block the rad again. What you need is a filter in the top rad hose to catch the rubbish BEFORE it gets to the rad. The filter I use has a s/s gauze inside with a screw cap to remove & empty the filter periodically.