There are many avenues to pursue this. Some are more legal than others. If it's currently registered, any police officer or courthouse official with access to the dmv system can find the current owners name and address. It's not legal for them to do this and they can get in trouble for it though. So if you have a friend in the business be sure they remain anonymous.
I work at a dodge dealer and compiled a list of all the muscle cars we sold new and did a Google search on them all. Came up empty handed 95% of the time. Have had better luck tracking them down via local car shows.
A few years ago I went through all of my old records trying to find the vin# to a 68 Camaro that I owned at 17 or so.
Couldn't find any paperwork with the vin on it and the local tag office had no record of it either.
With all the crap that was pulled in that car some of the old/retired local officers probably could give me the vin# from memory
May have to start looking again now since you have me thinking about it again