I have a 73 duster with a 340 in it and going down the road it will run 160 all day but when you stop, it warms right up. Climbs to 210 after about 10-12 min. This is after buying a 1863216 fan with a clutch on it after running a reg 6 blade fan on it to start. I have a universal fan shroud on it now. Didn't have a shroud to start. Warmed up a lot faster before i bought the 216 fan and put the shroud on. Within a couple of minutes it would get to 200+. Any ideas of what else to do. I know it's not terrible now but I'd like it to be cooler at idle. I don't know what it has for a thermostat or if it even has one in it.