The Italians too had experimented mounting this engine to their car originally, but it was dropped in favor of the simpler in-line twin.

1961 saw the launch of two estate models, 700 C (C for Combi) and 700 E (E for Economy), both featuring a larger 643 cc engine but with different power ratings.

In 1962 the sedan, too, was equipped with the larger engine, leading to the 650 T (T for Thondorf, the location of the manufacturing plant in Graz).

Going through homologation in the Group 2 racing class, they successfully participated in motorsport events, competing with its Abarth sister models.

In 1966 the Polish driver Sobiesław Zasada won the European Rally Championship with a Steyr-Puch 650 TR II, the smallest vehicle ever to achieve such victory.

In 1969, due to decreasing demand, it was decided to adopt not only the body but the complete drivetrain minus engine from Fiat.

Despite restrictive licensing terms from Fiat, quite a few cars were distributed outside Austria, most of them in Germany and Hungary, as well as in Finland, imported by Sisu Auto.