"Parts with appeal", it's been referred to many times. It might have been the "pin up" girl appeal to the Korean War soldiers and hot rodders

From the 1954 Hot Rod magazine issues

From the 1953 Hot Rod magazine issues

Above: Mamie Van Doren (discovered by famed producer Howard Hughes 1949 on the night she was crowned Miss Palm Springs. Hughes launched her career by placing her in several RKO films. 1951, she posed for famous pin-up girl artist Alberto Vargas, the painting of Van Doren was on the July cover of Esquire Magazine. http://en.wikipedia.org/wiki/Mamie_Van_Doren The above is from 1953

Above: Merry Anders (actress "How To Marry a Millionaire")

From the 1952 Hot Rod magazine issues

This last one is the segue into the next post, about the record business Hot Rod Magazine went into