If by plenum you mean the common area of the manifold that feeds the intake runners then volume is not as important as the design allowing the runners to pull in all the air they need.

As long as the plenum is not restrictive and does not seriously disrupt the flow pulled into the runners, the length and size of the intake runners is more critical to the tuning and power output of the motor.

Using the inertia of the fast moving intake runner air to force air into the cylinder after the piston starts travelling upwards with the intake valve still open is where good induction systems can help an engine make extra power.

If your intake plumbing is too big and you didn't have any restriction problems to begin with then you are loosing power cause the slower flowing air will not provide the same induction tuning as a smaller and faster flowing system would.

So yes, there is such a thing as too big.