Hi guys... Im actually running about 70/30 coolant and it actually used to run at 190 without a shroud not too long ago.
This could be your problem. with 70% antifreeze, there is very poor heat transfer. Pure water offers excellent heat transfer, but is freezes and rusts. Anitfreeze offers freeze protection as well as corrosion protection. The drawback is poor heat transfer.
For your location, you probably only need freeze protection down to zero degrees. That is about 33% antifreeze, 67% water. Even for severe cold climates, 60% antifreeze is the most you should run.
At 70% antifreeze you are unable to transfer heat from the coolant to the air unless you have a HUGE radiator. check out this website for mixtures needed for freeze protection levels:
http://illuminations.nctm.org/lessons/PercentConcentrations/Antifreeze-AS-DontFreeze.pdf
Switching your coolant probably had the most effect on cooling down the engine.