I recently installed a new engine and previously had done the clock/oil gauge swap. This time I put the factory sensor down by the oil filter, so now I have both idiot light and psi gauge, easy as pie.
Just as an fyi...It can also be had through Gauge Marks to replace the amp meter. I think this would look more natural as you don't have a hole through the lens. Really, how often do you look at the amp meter?