One day this may be a comprehensive list of all cars from 1975 and before shown on Google's Street View, but with some exceptions. Only cars on the road (whether parked or driving) or in cars yards/workshops will be included. We won't be showing cars parked in people's private gardens or driveways, no matter how rare the vehicle.
There probably won't ever be a full collection of pre 1975 cars that were manufactured until the 1990's outside their "home" countries: VW Beetles in South America , Renault 12s (and some other models) in Turkey and various eastern European countries, and Fiats made in former Eastern Bloc countries. There are hundred of thousands of these vehicles in daily use, and to an untrained eye indistinguishable from the originals using Street View. There is a possibilty that as the collection increases other cars will be added to the list.
Some cars where manufacture continued after 1975 are included on the list: North American, Australian and Western European VW Beetles, Renault 4Ls, Minis (original version, not BMW) and various Fiats. Porsche 911s are included where the probable date of manufacture is evidently before 1975, but we are sure that some may be missed. The same applies to North American pick up trucks.
Only one view of each car is included, hopefully the best, but usually the first time it was encountered. If a car is being driven on the road it may be visible in hundreds of locations along that route: you can "follow" some cars for 10 miles or more, with a different view on each click of a button.
Likewise for car events, only one view per event. For example, a Google Street View car followed the 2009 Mille Miglia in Italy, giving many thousands of excellent views of the 389 cars that competed the event and the hundreds more that followed it. If the car is shown on a different event, or in a different country, a new entry will be made.
Only thumbnails of the individual cars are shown: if you click on the "coordinates" link for each individual car it will take you to the Google Street View map with a full sized image of the car.