355 what next

The real question is "what do you want to do with the car?" The parts you need depend on your goals, and what heads and cam you already have. Tell me what heads and cam you have, what kind of car it is going in, what rearend gear you want to run, and whether it will be a street-only, street-strip, or race-only car. Knowing the answer to these questions will get you much closer to having the right combination of parts. Too many guys put in the biggest cam that they can find, or the biggest double-pumper carb that will fit. This usually leads to REDUCED performance if the rest of the engine combination does not match. A good engine must be a completely matched combination of parts. Putting too big a cam with low compression, or too big a carburetor for stock heads are 2 common mistakes. Tell me where you want to end up and I will see if I can help you get there.