With your engine full of coolant the intake or the head should be near the same Temp . You said running down the road ? Say 55 MPH with a 370 and a TH350 205 degrees is not bad . On a HP car 165-180 stat is the way to go . Also what Type of Cooling fan are you running ? And are you running a trans Cooler ? Is This your 31 Ford your Talking about ?