I doubt it's a 396 first off. You could go with a 600 CFM Electric choke carb, or a Q-jet. Performer manifold, or a stock manifold would be fine. The cam in mine is a Crane 216/228 .454 lift. Any four tube headers would be fine. Head ID is as simple as looking at the numbers on the center Ex. port. (Try this
http://www.pontiacstreetperformance.com/psp/headID.html)
What is your rear gear?
Good luck with it!
BTW, many will say that you should save your $ and build a 400 or 455 instead of dumping it into the 350. Really depends what your gaols are, but it may be something to consider.