(i’m a newbie) 73 duster, stock, first time running in 40 years (for more than 10+ minutes) was a few months ago, so not sure if this was always a problem or not
OK, that is a start. Have you checked at just idling, or have you gone down the road. Does it run hot driving? Does the car have AC? does it have a clutch fan, does it have a fan shroud?