Radiator hot on top, cold on bottom

I got red 50/50. Radiator bran new, shroud good and in place. I've been driving and building motors for a very long time. This is just something I've never seen, heard or dealt with. You guys have been great, I was hoping for someone with a different view. Motor runs excellent, gets excellent fuel mileage too. Just runs hot on long pulls. Was on 25 last week from Colorado going into New Mexico and climbing that last hill before the scale it got to 230, engine light came on but I was at top of the hill. Shut it off and coasted down. Fired motor back up, temp at 180. Got to Trenton, shut it off, found Radiator was half hot, half cold. So I installed new OEM detroit water pump. Still running 200 on flat ground and Radiator still half hot, half cold. Now I'm wondering if maybe I got a bad head. Just trying to get some input before I get back to shop and pull head off. Again. Haha the joy of having trucks..... thanks again guys, maybe I'm missing something

 

Guage is correct. Already installed 2 new 190 degree thermostats, and took back apart to recheck them. Not adding any antifreeze. Fan is working correctly. When I installed waterpump, had bleeder valve on top radiator hose open, when Guage reached 190 or so, they opened, antifreeze came out bleeder, shut bleeder valve off, added gallon and half antifreeze. I just don't get it...

 

3rd run. Bout 13k on engine now. In Oregon waiting to unload in morning. Gona load in Washington and head to Oklahoma. Shop is in Ft Worth Tx. Just wanting other brains on this, maybe something I missed. Wanted opinions and ideas before I pull head off and have it checked. It is possible to get a bad head. We got one couple years ago, but man, I'm tired of working on the ole girl when I get home. Haha

 

Thanks