I have the older version of that car, a 64 Custom 500 and they are a really sweet ride. The 390 is a true "muscle" car engine, but isn't necessarily a gas guzzler. With my 70 Galaxy 500 that I had years ago, it got 20mpg when driven like an honest man, but when driven like a man who has just stole something, it dropped down to about 10. That looks like a pretty good start for an easy to finish project. But I would really check out the rear quarter panels and the rockers, floor pans etc. for rust repair and ask how he repaired them and what he prepped them with before he did? Enjoy if that's what you decide to do.
I love the stacked headlight galaxy/fairlanes. my 4X4 high boys 390 runs about 17mpg when empty..... still not bad for mileage.
haha first off... wrong place to ask that question and as for my answer.... who cares how much its worth... unless you buy the car planning to sell it.... just speakin my maverick mind