67 Dart Overheats!

Overheating at a standstill usually points to a radiator flow problem. Have the radiator flow tested. Any good radiator shop can do it. They can also recore it with a 3 row core if the need be. You shouldn't need to upgrade to a 26" radiator because the 22" is what came in that car and it was fine until something happened to it. Plenty of B/RB engines are kept cool with 22" of core in an A body, so the problem is not that the radiator is too small, the problem is that it's not doing its job. Yes, the addition of the fan shroud will not hurt a thing. I would certainly not have a car without one. The cooling system isn't complete without it.