The way the car looks it's probably easily a $20K-$25K car.
The only way you're going to get that number up would depend on options, originality, numbers matching, documentation etc....
For instance:
4spd
vs Auto makes a big difference
Original fender tag and or broadcast sheet makes a difference
Whether or not the bumper option is original to that car, or whatever cool options it might have ?
Is it all steel or all full of bondo ? Has it been restored? What was changed ?
Do the numbers on the engine/trans/body match ?
All these factors play into the value.
If it was a fully restored #1 car it could be worth up to $50K