85 RX7, 75,000 all original, what's it worth
 

My father bought new in 1985. Has 75,000 miles and is all original. Everything works except the hatchback strut. Drives perfect and looks great in and out. Meticulously maintained with extensive service records. He even has a record of every tank of gas. I am thinking of selling it but do not know what it's worth? I have more pics and can take pics of svc records also.

Any ideas?