I once had a similar issue on a 74 duster 360 I bought from my brother in law. But I knew what the problem was. He ran it into a parked car in Seattle, when he was "celebrating" his birthday. In the wreck he shifted the front end over a couple inches. I had no money to have the frame straightened, so I cut off a couple inches from the ends of the fan blades. Problem solved. Never had an overheating problem, even running 100mph +, for over a 100 miles in Eastern WA, in the summer.