Do what the other guys said... Check your compression before you do anything else.
The heads on these old engines are pretty noisy. I don't know if any amount of rebuilding will change that, though. If I was looking for more power, I'd check the compression, and then if that was okay, start looking at intakes an carburetors.
Of course, I haven't looked at anything in the carb department, so I can't help you there. Off of the top of my head, I'd say I'd probably switch to a 2bbl setup just because it seems like less screwing around and probably better performance for the time and money. Of course, I could be completely wrong. Do some research and then decide what you want to do. It's your truck and you ultimately have to make the decision as to what gets done.
