1960
Formula Junior of 1959 was an international class for single-seat racers with engines from standard road cars. In 1960, some enthusiasts at Saab's combined testing and competition department decided to have a go at Formula Junior - even though the engine was well below the permitted displacement of 1100cc.
Taking an approach that was different to the conventional was not unusual for Saab and this case was no different. The engineers at Saab constructed an advanced monocoque car in contrast to the space frame designs of their competitors.
The three-cylinder two-stroke was installed, horizontally, in the front of the gearbox in the front of the car.

The Saab Formula Junior was, naturally, driven by the front wheels. Engine output was around 86hp but the weight distribution of the car put 70% at the front. The Formula Junior was fast on the straights and could brake later than its competitors but it suffered from excessive understeer on the corners.
The Saab Formula Junior was not fully competitive and after a couple of seasons the racing of the car was discontinued. Only two cars were ever built and were driven by Gösta Karlsson, Carl-Magnus Skogh and Erik Carlsson. One of the cars is on display at the Saab Car Museum in Trollhättan.

1964
Like the Saab Formula Junior and the Saab Sonett Super Sport (Sonett I) the Catherina began life as the personal sports car project of Sixten Sason.
Sason conducted freelance work but was soon commissioned by Saab to adapt his design for full scale production. Work on this commenced in January 1963 and by May work began on the assembly of a prototype at the Svenska Järnvagsverkstäderna (ASJ) workshops in Katrineholm (hence the car's name).