A year before the new Autódromo 17 de Octubre was opened ten miles across town, the Automóvil Club Argentino organised two international Formule Libre races in February 1951 in the city’s Palermo district. A short variation using both sides of the tree lined Avenida Costanera Rafael Obligado adjacent to the airport was chosen with a parkland section to the southeast. Mercedes sent three 1939 W154s for Juan Manuel Fangio, Hermann Lang and Karl Kling in its first post-war outing, but were beaten by José Froilán González’s ACA-entered Ferrari 166 on both occasions. The 1957 Buenos Aires 1000Kms was held on an extended version of the track with oncoming traffic at speeds of 150mph or more on the Costanera only separated by straw bales. It ran around parks at either end of the course. Stirling Moss later described it as “bumpy, poorly marked and extremely dangerous” and a chicane was inserted behind the pits after first practice on safety grounds. The Fangio/Moss Maserati 450S led convincingly before retiring, which left victory to the Ferrari 290MM of Masten Gregory, Luigi Musso and Eugenio Castellotti. Moss took over the third-placed Maserati 300S and snatched second place in the closing laps.
