I believe it is a Mocal and provided by Canton Racing, Pegasus Auto Racing and Racer Parts Wholesale.
http://www.cantonracingproducts.com/
http://www.pegasusautoracing.com
http://www.racerpartswholesale.com
It opens at 180 degrees. Not good to have the
oil too cool.
MOCAL thermostats are designed to prevent engine
oil from flowing through the
oil cooler until the desired temperature is reached. Prolonged use of engines in conditions that oil cannot reach optimum working temperatures will cause sludge formation and crankcase oil dilution, leading to excessive wear especially in the cylinder bores. Thermostats combat this by regulating oil flow to accelerate warm up. This in turn reduces drag, helping to yield optimum engine efficiency and performance. The proven design and reliability of the MOCAL thermostat make them the choice of automotive and marine racing teams world wide. They are also well suited for industrial and aviation applications..
Roscoe