Yes to headers, cam if you can manage the swap, intake if you can find a cheap aluminum dual-plane(i.e. less than 150), K&N(added out of habit), perhaps a smaller(600 cfm)Holley or Edelbrock(I recommend single inlet, vacuum secondary, electric choke)carb or non-computer Quadrajet from 76-80 GM vehicles with a similar engine size, non computer distributor from 76-80 GM vehicle or aftermarket street distributor. You will also be limited by your likely VERY tall rear gear ratio. I recommend either replacing the gears with a lower ratio, such as 3.23:1, or swapping out the entire differential from a different G-Body, preferably one with a posi.
I'm not very good at conveying information well so please feel free to ask any more questions.