Washington Revised Code Title 46. Motor Vehicles § 46.04.161. Custom vehicle

(1) Is at least thirty years old and of a model year after 1948 or was manufactured to resemble a vehicle at least thirty years old and of a model year after 1948; and

(2) Has alterations to one or more of the major component parts listed in RCW 46.80.010 that change the appearance or performance of the vehicle from the original manufacturer's design or has a body constructed from nonoriginal materials.