"True they will give you WOW bragging rights, but that's about it..."
We put on headers for the same reasons we put on 15" wheels with big and little tires and a dropped axle. It's because we like them that way. I even had the headers in my '40 coupe ceramic coated. This hobby is way to much fun and we spend our money on what we like. I suspect you have made changes to your car based on what you like.I wonder, just why do you want headers on your '47 Ford? Is it a race car? Do you intend to go out and bow the doors off of other cars that you encounter on the blvd?
It is a well documented fact of life that headers on a stock engine will not add anything to the performance of the vehicle. True they will give you WOW bragging rights, but that's about it...