Think this is worth $4k??
Nope. Not even close to $4k.
I bought my '74 Duster a little over a year ago and paid 2k for it. No rust, good interior, I even drove it around the block. Sure, the /6 turned out to be terminal, but it still said "runs and drives". And when I say no rust, I mean California no rust. As in, the paint on the trunk pan is as shiny as the paint on the outside.
With the rust that one has, I wouldn't give more than $1k. And its going to be a lot of work too. At the very least its going to need lower quarters, trunk extensions, and the driver's side floor pan. But I'd bet its worse than that. And something is definitely wrong with the suspension on the driver's side, its sitting on the LCA to get that low. I'd say that one's closer to being a parts car than a good start for a project. Only real advantages are that it already has 4 speed pedals and a floor shift column.