Builds own Jalopy. Washington, D.C., Feb. 2. Thirty dollars was all it cost Robert Preston, 16-year-old high school senior, to build this midget automobile. Weighing approximately 250 pounds, the 'jalopy' is powered with a washing machine motor of 3-4 horsepower and has a maximum speed of 20 miles an hour. His license tags for this year will cost 32 cents, 2-2-39