How much is it worth?

My uncle has a 1984 gran nat that he bought brand new in 84. The car has the original engine, turbo and drivetrain. The car has no rust and has original body panels. The interior is in fair condition and has factory seats. I was wondering if there is any collector value for this car and what its worth. I once read in GMhighperfomance that the blocks inthe 84's and 85's could get as much as 4grand. Any help will be appreciated.