General Motors, whose car-studded Motoramas have become one of the brightest offerings in auto showmanship, decided last February to bring belated glamour to the plain-Jane diesel engine. Beside Soldier Field on Chicago's lake front, the company strung out eight miles of electrical conduits, laid 500,000 sq. ft. of reinforced paving, built a permanent, 204-ft.-long bridge over busy Lake Shore Drive. This week General Motors was ready to raise the curtain on "Powerama," a $7,000,000, 26-day, seven-day-a-week diesel opera.
In rainbow-colored Dieseland, divers will splash into four feet of water in the world's biggest dump truck (50 tons), and the public...