Help with radiator

Try another 160 thermostat. I think I've had a a couple of bad ones over the years.

Do you have a lazar heat gun that can show you if the rad is actually cooling ok, are some of the tubes plugged from the factory. Use the heat gun and make sure there is no HOT spots on the rad, where a tube is possible plugged.
Check the coolant temp out of the motor and the coolant temp leaving the rad, is the rad cooling enough, you may have to run the engine a bid to simulate some air flow.

Just some thoughts, hope it helps.

Very nice looking car!!