There are so many different possibilities that you'll have a hard time getting anyone to respond to this question. There's just too many answers.
Here's a suggestion or two. Look around online for people selling 'crate 350 engines' then find a few that are in the HP range you want. Write down what they list for upgrades and mods to the engine. After you dig around a little while you'll get a pretty good idea of what mods you'll need to get wherever it is you're aiming for.
Some companies like Edelbrock list engine setups that they built - using all their own parts of course- that show many different HP and performance ranges. You can always check out their stuff and get the specs for what they did, and then shop around.
Once you've got a pretty good picture in mind, if you come back and dig around the site you'll usually find someone has already asked if Brand X's cam is better than Brand Y, etc... The old posts can give you a good street-side opinion of the advantages/disadvantages of certain parts and combos.
There's also an author named David Vizard who has written some excellent books on modifying Chevy Small Blocks. I found a copy of one on building short blocks on a budget in my local library to borrow.