It is only worth what some one is willing to pay for it, when they are standing there with the money in their pocket. I have sold some vehicles that the amount of time I had in them probably figured out to a nickle an hour. If you are doing this for fun and love the work will show. If you are trying to make money that will also show.
Black paint will show everything that is underneath. Just like a perfect black paint job is a thing of beauty. If you do this yourself you will learn a lot. If you pay someone else it will also cost.
A V-8 and a 5 speed is a kick. When you are up past 100 mph standing on the brakes and it's not slowing down fast enough.. That's when things really get scary! All you need to do is 55 on a road when the light turns red and the guy in front of decides to stop. If you are serious do the whole package. I prefer a car that is reliable, goes around corners, pull in and park next to a cop. Hopefully he won't look up from what he's doing. Last year I came off a light and stood on it, wound out 2nd gear. On the right hand side there was a white blur merging onto the highway. I looked over and there was a brand new BMW with the driver looking back at me. He had to pull in behind that old Mustang! All I was doing was enjoying my car.
Some people can flip cars and make money. My guess is the car is worth around $2000 as it sits, Drop a V8 in it maybe 3500. Add brakes and suspension you might be around 5000. Paint is like everything else, how much do you want to spend? Don't let me discourage you, the feeling you get when you put it back together and it runs! That's a good feeling! Sometimes I babble but I hope you get what I'm saying.