Can you ID this Mopar gearbox?

Thank you all for your useful opinions...

The trans is not very pricey : 500€ complete with lever and bellhousing. Usually, here, an A833, all by itself, is sold for at least 1500€.
But I don't know if this transmission would fit my '71 slant-six, if the Inland shifter would match the Demon floor opening, and also if my driveshaft could be reused (I currently have a A230 trans and a 7 1/4 rear end).

I'd love to have a 4-speed trans, but my Demon is matching and I do not want to do something irreversible.