I've found this similar car, as Hindustan Ambassador 2000DSZ Avigo from Howrah factory.
According to the garage where it was, the car was "fresh from the factory" meaning that they bought it from Howrah factory as it is.
In that forum, someone wrote "...is owned by Hindustan Motors Limited as per Vaahan App. So most likely it was a test mule."
Gosh, this Ambassador limo does look very close to my puzzle car, but I have looked into this a little deeper and can find no connection with the Howrah factory you mention and the converter of the Puzzle Hindustan. Sorry!
I realize this is an old thread and Djetset hasn't visited this site in over two years, but this puzzle appears to have been derailed by misunderstandings and apparent contradictions that I feel compelled to clarify:
1. The term "Howrah factory" isn't a reference to a coachbuilder. I've reviewed Oguerrerob's source, where this term is used as verbal shorthand for the manufacturer Hindustan Motors:
"He had another model of Ambassador with stretch door and shorter boot space. Firstly I thought it has been modded but everyone from Garage told me that it is in original condition as they have seeing it in as it condition when it was bought from Howrah factory. They insisted for 'Fresh from Factory' ..."After being constructed at Hindustan's Uttarpara factory, Ambassadors were generally distributed through a hub facility in nearby Howrah, the site of a train station that connected Hindustan's manufacturing operations with the rest of India. The user is simply saying that the people he met at the garage insisted the car was already in limousine form when originally purchased from Hindustan Motors.
2. The car is registered to Hindustan Motors. Others on that forum were able to look up registration data based on the plate. They discovered that the car was still registered to Hindustan Motors (as of 2019) and came to the conclusion that it must have been a "test mule" or "one of the prototypes that never made it to mass production." I have no clue how vehicle registration works in India, so I can't comment on this.
The two cars appear practically identical to me and it seems reasonable to assume that their bodies were constructed by the same builder. Djetset clearly has coachbuilder information for the puzzle car. If the people at the garage are to be believed, then HM could have enlisted that coachbuilder's help in creating a couple of Ambassador limousines.
Of course this still leaves the puzzle unsolved, but hopefully it clears up the apparent contradictions.
