With the mods you have listed, except for the intake manifold and cams, I think you should be around 430 hp at the wheels. Maybe a bit more. The intake manifold and supporting TB and an aftermarket cam should put you in the 450-475 range I would guess. As far as cam recommendations, I personally would stick with Comp Cams as opposed to some of these smaller lesser known companies. Comp Cams has been around a long time and will continue to be around when these other small companies are long gone...or after they've changed their name 2-3 times and get taken over by some other dude or go out of business for 2 years just to return under new management, lol!!
Im getting 400 hp to the wheels in an straight line dyno "curve" tune and BBK LT's and catted X. Find a great tuner shop before you just add bolt ons, as stated earlier the variable cams do allot of work the push rods needed new cams to do....
Buddy of mine did LT headers and a GT350 intake manifold. He had to retain the stock TB as there are tuning issues when using the GT350 TB. Anyway, with the LTs, the manifold, and the updated tune, his car now makes power all the way up to 7600 RPMs. How much of that is attributable to the headers or the manifold is up for debate.