Ive got some questions about intake plenum sizes

[chevzilla396]

Ive heard that your engine gets best power high and low end if your intake plenum is the same displacement as the ci of your engine. Say that you have a 350 ci engine, would you find the ci of your intake including the intake runners or only measure the plenum to get 350 ci? Also would you need a smaller plenum for a turbo applacation? if so how would you figure out what size of plenum you need?
-JT