...I have stumbled across a Fairlady 2.0 JDM 70 but I can't very much on the net at all about them. I've established they were sold in the Japanese market to avoid tax on large engine cars but I dont know if they were ever exported.
Is there anyone who knows how many were initially produced, how many were exported? I think it would be difficult to say how many survive today.
richiep has covered most of the bases, but I'll add a couple of things.
A 1970-built Fairlady Z (S30-S model ) or Fairlady Z-L (S30 model) will have an 'S30' prefix to its chassis number, and that's easy to check: It's engraved onto the firewall sheetmetal just above the brake booster. It's also stamped into an alloy tag that should be attached to the RH strut tower in the engine bay, and the script on that tag will all be in Japanese. Note that the (basic, no frills, 'Standard'/'Z-S') Z and ('Deluxe') Z-L models both shared the 'S30' chassis prefix and the same sequential body serial number series, so there's no way to tell whether an individual car is a Z or Z-L from the chassis number alone.
The 'no frills' Standard Z would have had no rubber trim on the bumpers, no hubcaps, no carpets, no radio (and therefore no antenna), no heated rear window and no clock - amongst other things. Usually the Standard had a 4-speed trans, but an Automatic transmission option was phased in towards the end of 1970, and an individual buyer could up-spec a car somewhat by paying for a few extras. After 45 years most cars get modified somewhat, so keep an open mind about spec details.
The Z-L 'Deluxe' model is much more common, and had all the gizmos and gadgets of the Export models and more besides. Again, after 45 years anything could have been modified / swapped, and a totally bone-stock car in the spec it left the factory is now very rare and unlikely.
Both models had the two litre L20A straight six engine with twin 38mm Hitachi-SU carburettors. In layout its almost identical to the L24 in export models. Engine number is stamped onto a flat pad on the engine block on the RH (spark plug) side, near the join with the cylinder head. Engine number prefix should be 'L20'. If it says 'L24', 'L26' or 'L28' then it's not the original engine block. There's an engine block casting date code on the LH (exhaust and inlet) side of the engine block, down near the sump join. This can be decoded to show the casting date of the engine block (and hence help to discern whether it's the original block).
Most other mechanical componentry is identical or very similar to the contemporary Export '240Z' models, so no worries there.
Nissan manufactured around 950 Fairlady Z and Fairlady Z-L models in 1969 and around 3,400 in 1970, so if the particular car in question has a chassis number below 'S30-04504' then it will be one of them. None of these cars were officially exported by Nissan as new cars, but a fair few made their way out of Japan during the 1970s and 1980s in the hands of US servicemen who had been posted to bases in Japan and took the cars home with them.
Appraisal of any car for sale should concentrate on the condition of the bodyshell itself, so please look out for rust, crash damage and evidence of any poor repairs.
If you have any specific questions then by all means post them here.
Good luck!
And as many other details as possible. You have got my full attention with this topic! 