Why does my 5.0 love to run at 210F??

[BilLster]

Well it doesnt say where you live but I always run about %50 antifreeze and %50 water and a bottle of wetter water.(in another post Chris sayes not to run more than 20% coolant I am going to ask him about this because I've always been told coolant also raises the boiling point so maybe this isnt good advice but try wetter watter)

To me I wouldnt say you were running hot . your normal tstat would be 192 so even with a 180 it doesnt open till 180 so its not designed to keep the engine running at 180 just to restrict water flow untill 180.

it also says you have a hi flow water pump we had a problem with a cascar with a hiflow pump that turned out that the flow was to fast for the water (100 water in rad) to absorb heat from the block , we switched back to a stock style pump and it cooled down. I dont think this is your problem cause 205-215 isnt really hot at all.

I would try a better gauge or even see if you can borrow a thermal gauge to test temp. I would add some more coolant to see if it helps with heat transfer.