My 3.6L engine loses steam above 7k RPM and although I love how the car performs, I've always been planning on ITBs to help ease the restriction the stock throttle body and intake manifold cause. It'd be nice to make power all the way to 8200rpm. However, I picked up an old intake manifold that may help. It's a 90's ZR-1 throttle body fab'd onto an NSX intake manifold.

I realize that various engines will be different but I'm just looking for general background data. So for any of the stoker (and anyone that would care to comment) engine owners out there, what kind of power increase resulted when you changed out the intake manifold for something that flowed better?

Pic of stated hp drop at 7k for reference


Pic of abovementioned TB for reference


Pic of what's there now (similar to this)