Just had my 351M to 408ci rebuilt . I'm using a FlowKooler aluminum waterpump with a RobertShaw 180 degree thermostat and a new radiator with a fan shroud. The temp gauge normally shows 160 degrees just driving around street speeds, but running 75mph on the highway it will get to 180 deg and this is in 95deg Alabama heat. Is this too kool for this engine?

 

No.........

 

I'd use the 185 thermo year round. 160 is a bit cool.