I don't know what remains to call this one "solved," but I will send you a link to the video mentioned above (with English subtitles). The video details the various components used, including the 4,680cc "S-47" type motor which the video says was originally built for use in a Star 660 truck. Here are a couple of still images from the video:
there are some bits from FSO Warszawa:
- steering wheel,
- front fenders with headlights,
- front and rear suspension,
- electrics.
Wheels are from FSC Żuk