As far as legality of resetting an odometer to zero, the only right answer is to check with your state Motor Vehicle Department. It'll likely be a different answer for each of the 50 states.
Kevin 1951 Chevy 3100 work truck Follow this saga in Project Journal Photos 1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car) Busting rust since the mid-60's If you're smart enough to take it apart, you darn well better be smart enough to put it back together.
