Things have changed immensely for Formula 1 teams. Up until the early 70s, Formula 1 teams were basically forced to build cars for other formulas, racing them as works teams or selling them to customers. The extra income was necessary, until commercial sponsorship matured in the mid 70s, and Bernie Ecclestone expanded the Formula 1 concept into a more viable proposition. Lotus, for instance, built Formula 3 and Formula 2 cars, selling them to customers in the early part of the decade. Lotus F3 cars were very common in 1970/71, rare by 1973, when Lotus had built the last non-Formula 1 car, the Formula 2 that became known as Texaco Star. There was some talk of a Formula Indy Lotus in the early 80's, but it never materialized. Brabham was a major race car builder, in fact the cars were very common in F2, F3, Formula Atlantic, and even in Formula 5000. The Brabham BT40 was the last formula 2/formula 3 from that constructor, in 1973, and a Brabham BT43 Formul...