Up to 16,000 kms range
The futuristic car was equipped with a steam engine that was powered by uranium fission and the powerplant was installed at the back. Tiny uranium pellets would be able to provide energy for up to 16,000 kms without the pollutants of the internal combustion engine. Of course, back then, the polluting effects of engines was not viewed seriously yet.
The Nucleon was just an idea and the concept was shown only as a 3/8 scale model. Perhaps not much thought was given to disposing of those radioactive pellets when their use ended… which is a serious matter today for nuclear plants. But the technology was far too advanced to be considered then and even now and so Ford set it aside – and maybe that was a good thing too.