I have a 350 .060 over flat top pistons, #906 vortecs, stock rods, federal crankshaft. I have the money now to invest in a cam, intake, and carb. The heads have the stock springs with a max lift of .450. So with a bigger cam will i just need to switch the springs? and what cam will give me damn near 400hp? what carb will be the best for my setup? should i use the edelbrock performer vortec?

This is my first motor buildup and im dropping it in a 1992 Camaro RS 305tbi Heritage Edition (White w/Red Stripes)

So whats the most efficient way to not crack the block with a bigger cam? And whats the most optimal cam for my application? Thanks alot!  

The springs will have to match the cam, but I think the heads are only good for .475 lift. The valve guides need to be machined to maintain clearance with the retainers for anything over that.  

Do yourself a favor and buy a good set of aftermarket heads. Most will give that 350 atleast another 35 - 50 horses out of the box. Plus they have upgraded valves, guides, retainers, springs and such. less trouble.  

The #906 heads are a fine set to start with...

But as someone else pointed out, lifts over .470" become troublesome with vortec heads as it requires a little more machining and "checking." And even with lifts below .470"  you can't just throw it together and forget it. You will need to use an aftermarket valve spring that matches whichever camshaft you so choose.  Retainer to seal clearance will probably become an issue but it's easily addressed by machining down the top of the valve guide...

You also need to determine if you have the compression for 400 horsepower. That is no walk in the park, it will probably require compression to be right around the 10:1 mark and a camshaft of at least 275° of duration and pushing .500" lift.

I'm an "Xtreme energy" series fan and highly recommend them (along with most everyone else) but if you have a very effective exhaust system you could get away with a narrower lobe separation and gain yourself some power in the process.

For the car to handle 400 horsepower it will probably need rear gears lower than the stock ratio and a slight upgrade on the torque converter...

Crack the block with a bigger cam? I really don't know where you're going with that one!