So what dollar amount is fair to you guys? I've negotiated more than $4000 off the price of a $7000 car, and $2500 off a $4500 asking price.
If he lists it for $500-$1000 he just gets a bunch of dreamers who'll waste his time because that's probably their whole restoration budget. Yet there is a good chance he keeps this car sitting around because he believes it's something special and worth restoring.
Drive your nice C-body over to see it with $1000 in your pocket. That puts you in a superior position to negotiate. Tell him you want the car, but it's $200 just to have it pulled from his yard. Compliment him for saving such a rare car, but remind him 413 cranks aren't easy to come by and his is likely shot (but thanks for being honest). Promise to show it to him when it's finished.
90% chance you leave with the car. 10% of people are dreamers, so it can sit. At least it won't rot away out there; get it at his estate sale.
In other words, I think $2000 is a fair asking price. Doesn't mean that's what you pay.