Running hot 65 Dart

Once and only once I had a slant water pump that the impeller was loose on the shaft.The bearing was good and didn't leak.Would run hot when driving and warmer that it should at idle.Just a idea. As far as your questions,Yes the block has coolant passages.Depending on your thermostat the temp gun should read within a few degrees of what your thermostat is.Lets say a 180*, at 180 the thermostat will BEGIN to open and should be fully open within 5*. So at Idle a reading of 185-190* should be normal.It may be more if the car has air.Other than that some other things such as timing,tune etc.also plays into the game.