Dart is totalled.. now what ?
..................so I can see where all of their numbers are being supplied from.
I GUARANTEE YOU that as low as these numbers are, this insurance company has already decided that you and your car is worthless. The ONLY thing these people will understand is a court case. Your problem, realistically, is that they can afford lawyers all day long and you cannot.
Forget their numbers, they are irrelevant. What I'd do is find a third party appraiser and have him estimate the value while ignoring the damage. Make SURE that he does a thorough job, looking at rust under the rockers, in the quarters, back window in the trunk. AND TAKE PHOTOS if it is a clean, rust free body. This alone is worth thousands of dollars for a restorable car. Show him your receipts and point out the obvious, IE wheels, intake manifold, new radiator, etc, etc. Obviously he cannot document engine internals, but you have the receipts.
And you need to come to a realistic figure for your labor. No court is going to pay you 20 bucks and hour for doing weekend work on your car, but your work IS worth something. If you payed shipping, as I did on a rear axle, etc, or drove as I did on an all -day outing to retrieve a disk brake front end car, THEN junk it out, THEN haul it to a scrapper, THIS IS WORTH SOMETHING. It was YOUR time effort, and money that YOU put into that car.
IF you do not have insurance to cover this, it's time to start sniffing a lawyer
Your receipts are VERY important. I would immediately find them organize and photocopy them, and NOTATE them if necessary by such things as "sticky notes" alongside the invoice in the copier, to document "what stuff was."
Little late now, but do things like when I find something on Craigslist, I save a SCREENSHOT of the ad, and if I talk to the guy with notes, I impose a note over the ad so I've got my notes all right there