So, you are looking for an original 1966 GT350 Shelby Mustang? Maybe it also needs to be a project. Anyway, here is a project for sale. It's currently listed on Craigslist in Palos Park, IL. The asking price is $70,000. The ad indicates that it was recently appraised for $68,000.
It's one of the original '66 Hertz Rent-a-Car Shelbys and is number 6S1681. All but about 85 of these Hertz cars came equipped with automatic transmissions, and this is the way this car was equipped.
The Hertz cars were available in white, blue, red, green, and black. Black was by far the most common color.
This one looks to be quite a project, but '66 GT350 project cars are getting rather difficult to find.
To learn more about all 1965-67 Shelbys, see the Shelby American Automobile Club World Registry.