The idea of torquing a bolt is not only to make sure its tight but also to preload it to a degree of its tensial strength. When the front pulley bolt is torqued its stretches slightly. This causes what ever it is clamping, in this case the front pulley, to compress slighty which in turn puts a constent load on the threads and under side of the bolt and in fact the whole bolt itsself. Thus the reason its so tight.

A trick i was taught was to place a socket over the bolt and wack seven bails of 5h1t out of it with a big hammer, thus compressing what ever the bolt is compressing ever so slightly more and hopefully ading the removel of the bolt..

Same as cutting the head off the bolt i spose.
Hope this helps.