I had a coolant leak on the "Cylinder Head Rear Plate" so I decided to replace that gasket. While I was in there, I pulled the carb to rebuild, the EGR and intake manifold to clean and replace gaskets. I got it all back together and it runs good but it overheats. I tested the tstat and it opens, the fan is turning and the water pump has been working fine. The heater does not get hot at all so I shut it down before it got above 1/2 on the temperature gauge

What could I have messed up?

 

You may have an air pocket in the cooling system preventing proper flow of coolant. Park the truck so the nose is up hill, remove the cap, start it up and let it run till it's hot. The bubble should work it's way out.

 

Yep, that was it. I just needed to give it a little more time.

She runs good.