I'm putting a rebuilt (like new) LQ9 in 1983 Z28, full dual exhaust, trailblazer SS intake manifold, 92mm throttle body, Comp 54-412-11 cam. I want to use the TPI air box because I like the design, but will it flow enough or should I build a larger custom intake? I am also considering the Ram Air system from Hawks but it only works with the Ram Air hood which I can't find.

 

The stock air box will not flow enough to support the full potential of the engine. If you look here Chad Spier(?) took a stock dual Camaro intake and modified it to allow more air flow
You should look in the LTx LSx subforum too

 

I guess I'll build a custom intake, probably build a cold air box behind the right headlight.

 

Try this: I'm not the first guy to do this, and it seems to work well.