[GoreMaker]

I'm looking to add a vacuum switch to my build to keep coolant from flowing through the heater core until the engine's sufficiently warmed up. There's a crapton of thermo vacuum switches out there, especially from Standard Motor Products, but finding the switching temperature and the normal state of these switches is nearly impossible. The only spec I've been able to find is for the PVS48, which has a switching temperature of 117f (that's a bit too low), but I can't figure out if it's normally open or normally closed.

Is there a place that lists these specs? Barring that, does anyone know of a specific switch that will actuate closer to 160f and is normally closed?