You did not expect it to be possible, but in June 1964, a 2000 km endurance test was conducted with a number of Fiat 850s. A bit short for an endurance test, but the challenge was to do that at an average speed of 110 km/h. Then it gets a bit more exciting.

850 duurtest

Proof can be found in a film on Youtube. First enjoy the commercials (not!).