The stock Big Rock body is 21.1" inches long over all. Most if not all of the Pro-Line 1/8th scale Monster Truck bodies should fit on any of the Nero chassis' (Original, Big Rock, or Fazon). They all seem to be around 19.5"-20" long. The Big Rock is a little different because of the bumpers, but if you don't mind removing or modifying the stock bumpers they should work. Here is a link to another thread that a number of people have posted pictures of different bodies on their Nero's. The Proline Silverado double cab is one of my favorites. https://arrmaforum.com/threads/aftermarket-arrma-nero-bodies.1941/#post-19078