whats needed for a blow through system

You need a carb prepped to work with boost instead of vacuum, you need a fuel pump capable of enough pressure to keep up with the boost and a boost sensitive fuel pressure regulator, and you need an ignition that can be dialed in to progressively pull timing as the boost comes in.

Simple, huh? LOL

and uh yeah...the turbo, wastegate and blow-off vavle....