In Spain and Portugal the highest economic growth was achieved during the final years of much longer dictatorships, the difference is that both dictatorships relied on technocrats and opened their economies more to foreign investment beginning the late 1950s. These were followed with joining international trade organisations and eventually signing free trade agreements with EFTA and the EEC while focussing on export-oriented industries. By contrast, Brazil (and Argentina) remained heavily protectionist, so much so that many of the automobiles produced in both countries were by the early 1980s based on antiquated technology. With few exceptions (like Embraer), but Brazil's economy remained dependent on the fluctuations of international commodity prices.
Additionally, Spain and Portugal's dictatorships seemed to be far more fiscally disciplined than their Latin American counterparts. The Spanish peseta even underwent a painful, but necessary devaluation in 1959. Chile is perhaps another example of a dictatorship that was able to achieve impressive economic growth. In 1973, Brazil's per capita GDP was 76% of Chile's but by 1998 had declined to 54%, showing just how more impressive Chile's economic growth was during the period. However, if we look at Argentina or Venezuela's economic performance after World War II they are even more abysmal than Brazil's. By the 1980s, most of Latin America was mired in a crippling debt crisis with high inflation that most Latin American governments allowed to spiral out of control.