I would not go over 20 for it. Non over the top restored it should go for 40K. 50K if it was a 4 speed, maybe a bit more.
Nice car. Love the 440, I have one and it flies. Check to see if it has a dana. I would add a bit more to have that.
Hope it has the back stripe like this car in the link I provided below. Once you buy a mopar, you will likely get the bug. Put Goodyear polyglas L60s on the back with steel wheels (hub caps optional) and that car would look so cool.
http://www.hemmings.com/mus/stories/...e1450280373119