Shure you can! But it's probably a really bad idea. If the cord (or fixture) is only rated for 60 watts and you run a 105 watt bulb, that is almost twice the wattage. Can you say "Fire Hazard!"? If you run twice the wattage that a particular light fixture is rated for, it will get really friggin' hot (if it doesn'y blow out straight away).
It's sort of like driving a car at 105 mph in a 60 mph zone - how long do you think you can get away with that?