New to A bodys, could anyone help me with the million questions I have

Thank you everyone for your help first and foremost.

Im new to A body Mopars with a 66 Barracuda. Im having a heck of a time finding fenders, quarter panels and floor pans. I would like to upgrade the brakes to power and also to disk up front as well as get rid of the tiny lug pattern the car has. Can anyone inform me of other make/ model parts that fit so I can do this? It needs a complete front end rebuild so the brakes would be done at that time as well. Any kind of cross reference information or web sight is GREATLY appreciated.
Thank you for your time and patience.
Brian