There was a time when a person could buy theses cars for 50.00 and up. How many are 4 door cars, shells, parts cars, C bodies etc. I have 4 door bodies and 2 door, but I don’t know what they are worth. Don’t really know very much about A and later B body values except what I read.
The past is irrelevant to what I said above. OP has current digital photos showing that they've snagged a 340 Duster
and an E-body within the last 10 years and his dad has shown photos of a shop and excellent restoration work.
Put bluntly, if someone can't figure out what to offer on the car in question after picking up some intact grail (for some!) cars, it sounds more like someone asking for peer review of a potential purchase. And that's fine. But it doesn't take a Ph.D. to peruse existing sales to find out how much a couple of framerails and rocker panels with a VIN number attached to a non-numbers matching '70 RR will run you.
It also depends on how bad the OP wants it. If I had that many cars stacked up, I'd throw the current owner of that hulk that very $50 offer and hell if he's offended by it. Screw the batshit crazy market and the fact that you can sell trash like this for $2,500. A rotted out unibody that needs every last panel short of it's rockers and framerails (if one should be so lucky) shouldn't really be worth anything over a few bills, because there's no increase in value if you start with a POS vs. something in decent shape. It is
always going to cost more than an already-restored car once it's done (and by that, I consider the $ saved in DIY to be offset by how much one breaks their back and huffs dangerous chemicals in the process of doing it DIY - even if they enjoy it), so why should the rotbox bring a ridiculous premium?
All the power to the OP for their abilities though - and for recognizing that the hood is the only surviving sheetmetal on the car. Some other ambitious fools might try to save more and wind up with a project they can't finish.
-Kurt