I have vague memories of fuel in Australia at the time being available to cars on an odd and even basis going on the last number on the number plate. (Odds one day, Even the next). If you ran out, hard bickies.
Same in NZ, we had 'car-less' days, so one had a sticker on the windscreen denoting which weekday one had decided to use public transport or get a lift; woe betide anyone caught driving on their car-less day. Whether that mad scheme actually saved a tanker or two of imported crude oil or not has never been announced. Kept the traffic cops busy checking and no doubt a fresh bunch of bureaucrats were set up to manage it.
It's possible the V8 would have sold well, but Nissan was busy enough turning out 6 cylinder versions with no shortage of demand.
As Enzo so eloquently points out, from the early 70's it was not a good time to be selling V8-engined cars, everyone was going sixes and fours and frantically down-sizing and being frugal with MPG as gas prices went up dramatically, USA especially so, with long lines at the gas stations due to shortages. Same in this part of the world, I can remember seeing gas stations having to close once they ran out.
Big block V8s got dropped from American cars from about '72 onwards, there was even one year where a V8 wasn't available in the Ford Mustang lineup and one had to make do with a turbo 4 or a 6.
Remember the big Leyland P76 - 'right car/wrong time'?
Besides, there were aftermarket companies like Scarab providing V8 kits for Zeds.