Tom - well said! People seem to think that I know everything about the vehicles I've illustrated - well, shock horror, I don't. Knowing everything about what other illustrators have drawn...
I am not sure why someone would think that we actually study the history of our subjects. If someone wants them drawn, that is the essential information. I have the same thing with photos. If the name is lettered on the car, or the team name is included, I know what it is. Otherwise, not necessarily. If there was someone with a chalkboard behind the car indicating "June 28, 1968," I will know when it was taken ... otherwise, I am pretty much guessing except for location. That I can figure out.
As to the illustrations, I can give you more stories about just getting to the research shoot or the background of what was happening rather than the details of the car. If the piece was for an article, i would always save it so I can look it up if questions come up. Whether it was getting caught in a landslide on the freeway, or shooting in a special situation, those I can pretty much give you.
When it comes to digging out these scans, the process takes a while so I will just go through magazines or books or whatever and pull what it says.
Since someone else will have intimate knowledge of a particular subject, it seems, I will just get it out there and look forward to getting the background back.