The number isn't random, as Plymouth sent only one Superbird to every two dealers in the United States. The Road Runner in these photos is a real-deal RM23 car (full VIN is RM23N0A178152).

The Plymouth Superbird was a dominant force in the early '70s muscle car scene. Based on the Road Runner – an amazing ... into a supercharged 6.2-liter Hellcat V8. It's not just a Hellcat ...