[shot12]

I have a 1969 gto with air. The heater core is leaking.There are 4 bolts that hold the heater/ac box from inside the car through the firewall with nuts on them. I have the nuts removed from the studs , 2 closest to the motor and the top one near the fender and the box is loose in the car. Do I have to remove the plastic fender well to get the fourth nut of as I can't see it from the top or underneath the car.Any help would be appreciated.

Thanks