Welcome. Interesting to hear about a convertible conversion done to such an modest vehicle. I imagine the cost to convert might have been as much as the car itself. But it sounds like you have a fun, unusual car. That said, I assume you don't know the name of the original dealer that had the conversion done. Since the conversions were probably not authorized by Datsun, it will be a challenge to trace it back to the original owner or dealer. Although CARFAX would probably not have records that go back that far, it might give you a starting point to trace back the last owners so you can research your way backward. Good luck with your quest and post pics.