The one I bought new had a 7 1/4" rear end and disc brakes. The disc brakes were a required $38 option. Asked the dealer about it and was told this was to reduce rolling resistance and increase mileage. That's what the Dart Lites and Feather Dusters were built for. Can't say if the changes worked, since I drove it home and yanked the /6, OD 4 speed, and rear end for a '32 Plymouth Coupe. The Dart Lite wound up with a 440, 4 speed, and 8 3/4 out of a wrecked Charger I had lying around (don't ask), and was sold with 6 miles on the clock. Hope this helps.