can anyone tell me when they stoped making the 280z and started making the 280 zx

I think it was 1979.

1975-1978=280Z1979-1983=280ZX

The last and best Z car was made in 1978. However, it does have a "confuser" (some call it a computer) on it. This does limit the amount of self-work you can do on that vehicle. But, the fuel injection works great.

well it is true the the ZX is kinda the "chubby" Z with all the luxury items, pw,ps,A/C,cruise,T-Tops ect.... however in 1979 they made a limited version of the ZX... the 280ZXR, only 1000 of them where made. it was basically the ZX without the X. the only luxury it has is A/C, not even power steering. I managed to find a ZXR for myself and from what I've been able to figure out... it does not have any speed limiting features, (126 mph then I ran out of roadway) the ZXR even being n/a has the T5 tranny that was used in the turbo cars of 83+. the other thing it has is what appears to be an R190 rearend but it seems to act like a 1.5 limited slip.... I havn't had it apart yet and the fact that it sat for nearly 10 years in a junk yard before i got the car leads me to beleive that the rearend just has something wrong with it thats making it act weird.

the main thing about the ZXR tho is the IMSA whale tail that was factory installed on the car to meet the homologation requirements of 1000 units.

they got fuel injection in 74.5 on the later 260Zmodels, the 77-78 chassis is by far the stiffest but heaviest and also has the biggest ugliest bumpers, and the engine wiring is not interfrated which allows for easy swaps and upgrades