Ford Racing makes intake runners that have very long runners, when the engine reaches 3,500 rpms a set of shorter runners opens up. My car needs something like this due to poor power below 3,800 rpm. Does GM have anything similar?

I think this would make a kick *** system for a tpi engine. That monstrous torque down low and the cubes to run up top.

 

The ZR1 Corvette had an DOHC LT5 motor with 2 runners per cylinder. As RPM's increased, the "second" runner would open.

...but no not really. Not anything you or I could just go buy and bolt on. There are several intakes available that flow more than enough to support the high end, and low end torque loss is minimal. For any racing motor, you never really see those low RPM's anyway.