Whats my Dart worth?

Insure it for what you have in it, I'm sure it is a lot. These cars are not cheap to build.

Yep, parts and a good guess on labor at say $25-$30 hr.
I once had a piece of jewelry appraised and was told it would retail for $1,200 then they proceded to tell me they wouldn't put a insurance value any less then $5,000. OK?
As far as resale value, who knows? Could go to a auction and bring 20k or 80k, if someone really had to have it.
I love the car and if i had the coin to buy i would certainly make it worth your while. I'm sure, if you wanted to sell, and could be patient the right buyer would be out there for you.