Pull the t-stat and throw it into a pan of water (on the stove) and watch it as it heats up. with a temp guage take note of the temperature the state opens. I have found several t-stats defective. I have had 180 stats open as 160 and 190 stats not open at all. There is a few that get through the cracks as QA is watching.
You could just buy another one and see if that works, but you would never know what the actual temp of your t-stat is.
SPEED SAFE, AIR RAM
Im putting together a .040 455 with Edelbrock heads (72cc), Eagle Rods, FLAT top J&E Pistons for 12:1, Harland sharp roller Rockers, Fluidampner, Edelbrock Performer RPM intake, and 750 Demon Carb. "GOT TRACTION"