"using no oil between the 1,000-mile scheduled oil changes—the standard maintenance interval back in those days."
1,000 mile oil changes?! The oil back then must have been unrefined....
That would have been very difficult to do, at 50 mph it would take 20 hours a day! I would imagine it was set up like a Le Mans course and just keep the car going all the time, short of fill ups and oil changes.
I wonder if they modified the fuel capacity? A stock tank would require at least five fill ups a day to accomplish this.