Help putting a value on a car
 

Hey, This is my first post here, I have a friend of the family that would be willing to sell me there 57 olds super 88 with 47k original miles. Repainted the original color (grey) the rocket motor was went through, as well as the trans. new headliner and carpet. It is NOT a j2 option though, just a single 4 barrel. And rust on the body ( she said there was very little ) was torched out, and new metal was put in place. Any idea what this thing could be worth?
Thanks IN advance

chris