moparx and Montclaire I agree.

I appreciate the help from all and I know it's kind of a long thread so I don't think all read all my posts. The radiator is brand new. Now I suppose a brand new radiator could be clogged, but as I also wrote and pictured, I had the engine out, freeze plugs out, water pump out and flushed the block out, bypassed heater core. Yes, factory shroud in tact.

It never runs HOT on highway nor idling all but that one time, and I now have 800 miles on it since engine out. I don't think the temp gauge is dead on, but it's close. It just shot up that one day in very hot weather in very bad traffic. And it did immediately drop back down as we moved on.

RapidRobert; stainless welding rod. Um, good idea.