A brief glance at the functional diagrams of the Amiga you can see that many parts of the Amiga operate as tuned ciruits (having inductance and capacitance in series) ie they only allow certain frequencies to pass through. You would have to totally retune the frequency of all parts of the board - adjusting inductance and/or capictance in each functional block.
It would be interesting to see what happens, although I'd imagine a black screen would be the result of a large change, and a very unstable computer the result of a slight change.
What you are suggesting is akin to moving BBC World Service up the frequency band to increase the amount of sampling rate of the braodcast but not retuning your radio, and hoping it will work.
