Here is a fast, cheap, and easy method for making a cold air intake for the Mercury Grand Marquis, Crown Vic, and Town Car.
1. - Locate and remove the Air Box from the car.
2. - Remove the Snorkle from the Air Box --
3. - Attach a length of aluminum Clothes Dryer Duct to the front of the Air Box, where the Snorkle was.
Cut Dryer Duct to length that allows the duct to reach forward of the engine bay.
4. - Re-install the Air Box, with Dryer Duct opening behind headlight.
5. - K&N Air Filter (K&N 33-2272) is used for high air flow -- AND -- the K&N air filter works when wet (others don't!).
This cheap and simple modification eliminates the restriction caused by the small-diameter Snorkle, while still allowing the maximum air flow of the Throttle Body during wide-open-throttle runs.

Picture shows completed modification:

Stock Air Box with Snorkle removed, Clothes Dryer Duct installed.

 

Don't be fooled by that idiot on You-Tube that cuts the bottom out of the air box, claiming there's "free power" and "better fuel mileage" in his so-called "Performance mod".
By cutting the bottom out of the air box, NOTHING is gained at all -- not more power, not more mileage, just more NOISE -- and HOT air from the engine bay is all that is available, thus defeating the whole purpose of a "Cold Air Intake".