Apart from talking about commercial vehicles you didn't really address what I said. Nissan 4WDs from the 70's still used? Which models? There are always exceptions, Celicas yes I know some and early Mazda rotaries are popular, but they are just a platform for the rotary engine and fancy coloured custom House of Kolor paint, no one cares about the car itself.
Go to MotorEx or Summernats or EasterNats or Powercruise, it's mostly Australian cars 1960s-1980s as well as some Americans.
Look at November car shows for NSW
http://www.ozshowcars.com/novnsw.htm
23 Ford Day / GM Day 2013 Queanbeyan
23 Car Show 4 Xmas [ Twilight Show ] Harrys Liverpool
24 American Car Nationals 2013 Queanbeyan
24 Great Lakes Historic Automobile Club Shannons Show N Shine Forster
24 WSCC All Badges Charity Swap Meet St Marys
24 Culcairn Classic Car Club Swap Meet & Show N Shine Culcairn
24 EJ - EH Holden Owners of Southern NSW Inc. Car Show Black Beach
30 Powercruise 1 Day Powerplay 2013 Eastern Creek
30 Bridage Aid Car, Bike & Truck Show Bargo
No "70's Toyota Day" running is there. In 30 years there will be Commodore Nationals like there is Monaro Nationals today and the Monaro Nationals will probably still be going.