Revealing mistake: When Carole and Jim rush out of Herbie to find Thorndyke under the bonnet, you can see that Carole is not Michele Lee but her stunt double.
Revealing mistake: In a shot of Thorndyke's car and the front and back of Herbie as they approach the finish line of the El Dorado, look at the back half and you can see that Tennessee is not Buddy Hackett but his stunt double.