I have a 400 coupe. Just got it put back together with a nearly 500 hp 455. Since the next step is paint, I have not installed any of the extra cooling parts for the 400 such as the upper and lower baffle plates or the plastic mastic pieces to channel flow straight into the radiator.

All I have is a custom 4 row aluminum radiator from Rodney Red, a stock 19 inch clutch fan and a OEM shroud.

Last weekend I was went to a local cruise-in down mid-town streets with 30 mph limits and lots of stop lights. Temps in the mid 90's and 60% humidity

My OEM Rally temp gauge never got above the 3/4 mark which is where it stops after the 190 thermostat opens