Ah, that is more demanding. Isuzu started with the British mkVI Minx in 1953. That was the side valve model, but each time it was facelifted in the UK, ie mkVII and mkVIII, it followed in Japan. The 1390cc ohv engine was introduced in the mkVIII so my guess is that that may have been the model used to be the basis for the Mercedes look-alike ........ because the wheels look more like those on the early Minxes, designated PH10s by Isuzu.
Isuzu of course continued with the Audax series of Minxes from 1956/7 - known as the series 1, 2 and 3 in the UK but PH100, PH200, PH300 and PH400 in Japan, - but stopped then to produce their own Bellel in 1964.
The PH300 (UK Series III) introduced the best engine, the 1494 cc, but if you can follow all that, I think that car was actually based on an Isuzu PH10!
