As someone who is constantly getting redirected to other things or otherwise distracted (Look! there's a cat over there...) I'll give him the benefit of the doubt on responding.
Generally speaking, the whole 'how rare is it/what's it worth' line of questioning seems pointless and suspect, unless:
- You know nothing about value and don't want to overpay or overspend on the project if you buy it (Good luck with that)
- You know nothing about value and are asking or selling for a friend, estate, etc
- You know something about value but not enough to trust your judgement and don't want to lose money when you resell (flip) it.
Any of the above are fine, even flipping, so long as you are up front and open about it from the start. Folks are more than willing to offer assistance and we all love to hear about another neat car surfacing. And in reality - flippers, Ebay and similar methods end up saving a lot good stuff and bringing it back out into the light of day.
I think option one is out since chrisnben posted photos of other cars he's worked on, owned, sold, whatever. And with no mention of anything in option two, it pretty much leaves option three as the motive. There's enough info online to establish some basic knowledge of scarcity at least, even for a newb (which he clearly is not).
Now, if you're talking production numbers/scarcity which was the original premise, that's another matter entirely since it implies a desire to save or preserve a rare car. Yet again, the poster blew any potential basis here by mentioning wanting to hot rod or otherwise modify the car. As someone pointed out, that pretty much screws the 'rare car' aspect. If you're buying it to hot rod, you're not buying it for its collectibility. Its value will be whatever you personally place on it, the sum of its original parts for resale, whatever.
A more likely post would read something like "Found a cool car, the fender codes/numbers indicate it really is a <XYZ>. How much is it worth as it sits and what can I do to it without destroying its collectible value?".
If you truly want a car, price (within your means) isn't really an issue. 'Value' only matters if you're planning to sell. And a rare car is only rare as just that - not as someone's re-interpreted idea of how it should be.
Keep in mind that this is my opinion only, and may not be worth the time you spent reading it. That's why I saved this until the end.