You know... I have a smooth feeling something indeed got lost. Written like this, it could be transliterated into Russian as СЗЛ, ЦЗЛ, С3(three)Л or Ц3(three)Л. To be honest, I think the text contains an information about S-3L (three, not Z - they're identic in Russian alphabet). As a proof: SMZ S3L was presented in 1956 and had a 7.5hp engine. But the maximum speed was just about 55kmh and, what is more important, it was a three-wheeler...
I'll have to find out more abou tthis car - it may well become some NAMI or SMZ own prototype or, or maybe there was indeed something called SZL and I may be completely mistaken.
Pictured are SMZ S-3L and a 1958 prototype called SMZ S-4A. Note how the design was meant to change - four wheels and a closed body, the ideas close to the car on a first picture.
Can I share the above article with text at another forum and try to get some information?