Overheating

I have a 95 Cavalier recently installed a new head. Now having overheating problems changed the thermostat and water pump also did a radiator flush. Its not getting hot enough to get in the red now but when I run the car awhile driving if I stop to make a turn the car shuts off and it will refire but when I put it back in drive it cuts off again and I wind up sitting a few minutes before I can continue driving on again. Any ideas on a problem would be greatly appreciated