[Orange97GTVert]

The VIN is stamped just inside the hood on the driver side fender apron in front of the shock towers. The A code should be in that. That won't tell you the car is a GT, but if it is anything but an A or K code it will tell you it is not. There was no special designation for a GT in 1966, just the engine code. Also check the data plate on the door jamb at the back of the driver's door, it will tell you the original specs of the car unless the door has been replaced and the tag doesn't match. The number on the engine block and transmission do not match the VIN, but they do have casting numbers that tell the date built, both should begin in C6, the C being the decade of the 60's and the 6 meaning they year 66. Most 66 Mustangs have had the engine replaced at some point, but not all. While you are looking at it, check the floor pans and behind the wheels for rust or rust repair, also look inside the trunk, under the trunk mat, early Mustangs were prone to rust in those areas. Good luck!