340 coolant temperature

As an added thought. 160 is not "cold" .....it may have a 160 stat in it which yes is the lower end of temperature. I run 180 stats typically but 195 is quite normal too. The 160's are not my fav but that's because of thermal efficiency etc which is a whole other subject.....

But I still say your issue is flow related and I suspect a collapsed lower hose...

Good luck let us know what you find