using nada, hagerty, etc. for market value??

With these cars, value is based on what someone is willing to pay. Its hard to factor. Any info on what you are looking at? Folks here have a pretty good idea of value per options, desirability and any effort put into the car (i.e. rebuilt engine, aftermarket goodies, etc). Pics and specs and you could get a good idea if the seller high, about right, or "oh my god you'd better snatch that up".