1972 Ford F-100 How to get more horsepower?

I would like to get more power out of my motor, what do you recomend? It has strait pipes with glass packs. How many horse more will headers give me. Also if I convert it to a 4 barrel carb, how many more horse. Whats the difference between a high rise intake and and a short alluminum intake power wise? What bolt on's will help me increase power? I only have a grand to spend. Thanks for the help.