Over heating 66 Dart

The radiator I now use is a 22" radiator. I can't seem to find my receipt so I don't remember the name of the radiator company I got it from. But it is an all aluminum welded radiator that has the exact appearance of the original radiator. It has the rounded tank on top and if it was painted black, unless you was looking for numbers or something it would look exactly like the original. I got the radiator off ebay. It is a 2 row radiator. My brother's 65 dart has the same set up I do and he has no shroud. But he has the original radiator. Although his is a 4 speed. I don't see how that can have anything to do with the overheating. However, I just remembered his has the dual point distributor, this is an ah ha moment for me. Maybe the timing is not right. We did set the total timing to 40 degrees. I wonder if the electronic ignition is not working with the engine properly? I don't know. I'm not a mechanic, my brother is. I was always the mechanic's helper! I understand how much of the mechanics work, but I am no mechanic!