At approximately 1900 Central time the airplane experienced a total loss of engine power and was substantially damaged during the forced-landing rollout. The pilot and sole occupant sustained minor injuries. The pilot subsequently told investigators he had purchased the airplane the day before the accident and was flying it back to his home airport. On the final leg to his destination, the airplanes engine experienced a total loss of power. The pilot attempted to switch fuel tanks but the selector would not engage the desired detent. After several attempts to seat the fuel selector, the pilot elected to perform a forced landing in a wheat field.