Here's a review from IMDb:
"Turismo de carretera" (TC) denotes a class of auto races very popular in Argentina. From 1937 to 1960 ordinary touring cars were used (mostly Fords and Chevrolets). Motors were souped-up, suspension reinforced, inessential weight (such as mudguards) removed, and cars were raced at high speeds over ordinary roads temporarily closed to traffic. Most of these were dirt roads indifferently maintained, and the sport was hair-raising dangerous; accidents and casualties were frequent. Most Argentine drivers made their debut in TC, among them the great Juan Manuel Fangio, who later went on to win the Formula 1 Championship five times. After 1960 the sport became safer, many races were held in dedicated tracks and local manufacturers produced especially factory modified automobiles adapted to racing.

Director Rodolfo Kuhn was one of the stars of the renaissance of the Argentine movie industry between 1955 and 1975. This movie, however is strictly entertainment. The script is naive (interesting ending, though) but the racing sequences are exciting. As a bonus, midway through the movie we have interviews with the greats of TC: Fangio, Oscar Gálvez, Juan Manuel Bordeu et al. The interviewer tries to discover what made them tick; the answers, of course, are ambiguous."