You can get some good stock four intakes and carbs that will make ok power but not as good as edelbrock. But will look dead factory under the hood. Same goes for manifolds that will flow enough to make good power. Usally some port work on factory manifolds is all that is needed if the right casting a choosen. But this is kind of art with the oem parts swapper guys. I can really help with all the part numbers needed to pull it off. But the 350 hp sounds possible.
I do think having the factory under the hood will be worth every penny if you plan on selling the car. If a buyer looks under the hood and sees intake and headers they always think the worst. Unless they know the engine builder and then still its a harder sale than oem stock look. No one complains if its four barrel and not a two. But headers will drop the pirce a bit unless they are a work of art in them selves.