1961 Chevrolet Impala SS Bubble top Chevrolet released the SS package in 1961 model year and produced only 453 of these vehicles (RPO option 240) with the following mandatory options listed on this numbers matching real car. This is not a clone or fake 1961 SS bubbletop! This is the real McCoy. It is said that approximately 10% ( Motor Trend ) of real 1961 SS cars are still in existence, and this is 1 0f 453 that were produced This was a frame off, meticulous nut and bolt restoration with a complete drivetrain rebuilt several years ago and is better than factory new, in show condition.