I'm confident my 225 is running at 180 deg.
Both new and old stat run up 2/3's up on the temp gauge. Stays there rock steady no matter the outside temp.
Heater feels good too.

My only concern is the gauge reading so high. Normal zone starts at 1/3 and normal operating temperature runs at 2/3's. For some reason I'd rather see it closer to 1/3 of the scale but feel that 160deg would be too cold.

It's a 1965 Belvedere. All original and we use it for family cruising.

Does the fuel gauge read off a little too? If so, the regulator behind the instrument cluster is probably going bad.

http://slantsix.org/articles/instrument ... nt_reg.htm

-S/6