It's really hard to tell what cars are worth until it sells (duh).
It needs a completely new firewall?
If so, then with new quarters, hood, trunk/extensions, parts-materials alone are gonna be ~$4k. If you farm out the body work/paint, you're looking around $15k. And that's probably cheap working like $45/hour.
Then you're probably looking at 2-3 years from now b/c w/o money, it will be sitting until you do.
So...keep it and drive the hell out of it; or...
dump it and someday save for a nice solid one not needing paint/body work; maybe someone else's project that's been painted and only needing drivetrain.