1976 Dart Overheating and other issues

dunno if its been said but if you still have problems after flushing, the radiator may be clogged. the fins clog with rust and sludge. either replace or find a shop that will recore. if you wanna get crazy have then put triple core in it. those lines between the fins are small, they clog,and back in the day when they leaked they were eliminated by ctutting them off and soldering sht at the tank etc. i agree the radiator looks at the least old and rusty. do all of the other stuff first if it still runs hot go after checking the rad out good.