The dilapidated Mustang was found in a field in Texas, It doesn't have an engine and most of the front of the car is gone. There's little documentation of this GT500 and what lied under the hood when it left Carroll Shelby's shop is a mystery.
Full article here: https://classics.autotrader.com/articles/this-lost-1967-ford-shelby-gt500-exp-prototype-has-been-found