I am getting ready to buy a 1966 convertible. The seller says that they purchased it believing that it was a true factory GT. The engine code is C. I have read that the GT package would have a A or K engine code. But I also read that neither of the high performance 289 engines were included in the GT package. If you wanted the them you had to pay extra to get the hipo engine. You did get GT badges, GT stripe, front fog lamps, dual exhaust through the rear valance, front disc brakes and the GT gas cap. The code shows that this mustang came out of the San Jose factory. Is it possible that this mustang has a factory installed GT package with a C code 289 CID 2 barrel carburetor? It also has a factory air/smog pump. Was this just on the cars that were produced in San Jose? Thanks in advance for any help