Steve,
I am experiencing similar results in Ohio, so it's not a Montana thing.
Just kidding . . . the SPF radiators are just THAT good. Seriously. Those temps are about identical to what I see. If it's not well over 70 (F) degrees ambient, I can't get the water temp to go over 70 (C) degrees.
I run a Robertshaw hi-performance thermostat with the really nice 3 machined bleed holes. My "by-pass" is blocked off! I'm maintaining those temperatures by flowing whatever water is going through those 3 tiny holes and just ambient air cooling the engine.
I have a 180* stat.
If you want it to run warmer, I suggest buying a replica with a lesser radiator.
