almost anything is possible in the customising world but : in your case it may be a little tough from what I see or know. The console in your 76 has the wheels to control the heat etc , the 78 up are different with levers so you would need a donor car to get all the cables, switches etc . Shifter and park brake are the same. Seats you can make work, if added power drivers then need to wire that up which is easy. Door panels won't match up to 76 doors cause of the handle and holes for remote mirrors , door locks. This is a paste of door info :
All
coupe doors physically interchange-however: 68 is by itself due to the lock/pushbutton being together. 69-77 are 1 style door panel and really 69-72 have no internal crash bar, while 73-77 do, but they interchange redily. Then 78-82 are another style door panel. It is not easy to make early
doors work on a late car unless you use corresponding door panels. Verts all interchange, but 68 is by itself, and the 73-75 has the crash bar .
....also the compartment behind the seats is different but that you don't need to change as it is not seen in the 76 as like in the big back window cars with the retractable curtain .
gas tank is bigger in the newer cars but the filler neck is a different location so that won't work for you. I seen jobber tanks out there that may be bigger to fit or you can get one made up to work in there.
.... just last tuesday I went to inspect a 76 coupe for a friend and he bought it after my approval ( ha ha !! ) we are going to go pick it up next week so I will compare it better with my 82 when we get it back here. But from what I recall seeing , you'll have some fun doing a swap unless you have a good donor car to rob.