Not to sound flippant but its worth what you are willing to pay. That said, if you are going to do a full resto know that the cost of that can be $50 - $100K (or more depending on your requirements). Additionally, you need to look at the market for what car in the condition you ultimately want this one to be in when done is going for. With these 2 figures you should be able to then determine what you should be paying now.
Currently, very nice V code E bodies are selling for probably $70 - $150K, so if you are willing to spend say $50K to restore it, then you shouldn't pay more than say $20 - $40K to try and stay in the black. This is all out of my head, someone who really follows the market can give you much more accurate numbers. All this is assuming you don't have an emotional tie to that car or that style of car, if you do then the numbers don't matter. Personally, I'd rather have a very nice restomod with a Gen III hemi in it, but each to his own.