How do modern cars regulate temperature so well?

Rad looks tight, great fit on that shroud. Could there a shroud under the rad to the core support so the car is not pulling heated air from under the car? I googled that fan control but came up with the PWM 150 model. Probably just a fancier version of your dial type. So your temp sender is on top reading the motors temp and the controllers sender is on the bottom reading the output of the rad. What happens if you run the controller cooler? What type of stat are you running? Id run that controller at its coolest level and see if the motor responds. if not it may be a circulation issue. I know with an electric pump controller (your could probably do double duty as one) you can run no stat (or just a restrictor) and have the pump off during warm up and start it cranking when the temp starts to climb.