If it is of MMM origin than a lot of mods have happened. Front springs on the outside of the chassis? Shock mountings above chassis height? Very low bottom of the body, if the chassis matches this something strange happened Rear axle mount with holes in it?
But I love some automotive archeology so more pictures please!
It bears a superficial resemblance to early 1920s racing Delages like the DH and 2LCV. But obviously not a real one as it's not big enough. The later 15S8 had a similar radiator, but sloping, not vertical.
There are some weird and wonderful things in Argentina and there were some very professional specials built there, usually - but not always - on American chassis. However, that thing sits so low I wonder if there might be a Riley 9 chassis under that body?