Hi Everyone, The dreaded heater core crapped out and started leaking. I've put this repair off for awhile but decided to dig in and get this done while I am quarantined at home . After looking at all the videos I could find on replacing similar year Mustangs, Cougars, etc... heater cores, it looked like my job should be easier. After all, my car only has a heater no A/C, and the dash is much more open. After unscrewing all the fasteners and bolts for the heater box I could find (and reach), from both the engine compartment (firewall) and the underside of the dash, the darn box will still not budge! I have spent a day trying to find what is still holding this box in place. I have not removed the dash. I really did not want to get that destructive (its in perfect condition). I did remove the glove box. Can anyone help direct me to the hidden bolt/s holding this box in place.? Do I have to remove the entire dashpad/dashboard to get access to a hidden bolt? I have the actual shop manuals, but I cant find what Ive missed. The engineering on this is ridiculous. It could have been sooo easy. I hoping someone has a simple trick. Thank you!