I recently picked up a virtually new 97 F250 in Prescott AR. 460, 5 spd, an absolute dream, particularilly for this kid from MN. Older and rust free is very hard to find. Question: I have the origonal window sticker and under the options side, along with the limited slip, 460 engine, 5spd etc it lists a High Altitude Package. Any ideas as to what it might consisit of? Truck certainly isn't running lean at sea level, and is an awesome performer. Thanks!