I did the heater core on my 1980 TTA. I already had the right fender off, so access to the bolts and hose clamps was easy. Service manual says you can do it by unbolting and dropping the inner fender, which is probably true. But, if you have the time and want to cut down on the frustration, I recommend you take off the fender. I have a '79 that I'm going to put a new core into. I'm going to try the inner fender trick first. If that doesn't work, I'm taking off the fender. It needs paint anyways, so not too worried about scratching the fender or hood in the process.
As others have stated, the studs are on the engine compartment side. You will need to remove the nuts on some, unbolt others. That part is pretty simple.
No need to take out the console. You will need to remove the ducting underneath the glove box to get to the core box. You may wish to remove the dash to do this, but you may be able to get away without that part. Just makes access easier if you pull the dash. That's up to you to decide.
Once the heater box on mine was out, it was a simple matter of unscrewing the thing to get to the core. However, there were a couple of screws that I didn't see and they were hard to get to. I ended up breaking the lid when I tried to pry it off. No problem, that's what epoxy is for. But, you may want to be a little cautious if your heater box is 33 years old and brittle like mine was. It can break easily.
Good luck!
Oh, and don't forget to reconnect the ground wire on the heater box!
