Get Leo Santucci's book on the late Chevy six. It is very good.
For a cam, a lot of the manufactures can grind you a cam. Want to talk to a human being who is doing something more then reading out of a catalog? Call Schneider in San diego. They have done my last couple of cams and they have been spot on with their recommendations.
Intake--If you want multiple carbs (and they do look cool on a 6) then consider the Clifford 2x2 using a pair of 38 mm 2bbl Webers. It is a little pricy but worth it. I have that set up on my 261 and it runs really well. Has hot water passages already cast into the floor of the manifold.
Head, you can get the bolt in lumps and go to town. Good three angle valve job, maybe some larger valves.
