Why will it never be a 500 again, a 500 is basically a 3 door with a list of additional parts, if the 500 shell is built up with all the unique parts then it will be spot on, even if a few are missing it will still be a 500 as its chassis number will dictate. Just not easy getting the parts, if you had a hpi recorded 3 door or a good rep to break then it may pan out, but some of the 500 bits will take a lot of effort to find. Would be a good project If you have the time, just don't change the colour of the original shell, and make sure you use a small core 205 block to build the engine,