It was the forerunner of the 240Z. It was badged as the Datsun Fairlady 2000. Saw lots of them while in Okinawa and they were a popular ship home car with the military, especially with the higher ranking NCO's and Officers who got their vehicles shipped back for free. They were also available in the US but were a little pricier. They could be ordered through the base PX (Post Exchange).
Before the 2000 there was the Fairlady 1600 and before that, the Fairlady 1500. They never had the Z moniker until the 240's came out. The early Fairladys as I can picture it, reminds me a little of an MG except just a little bigger.