Oldsmobile/Buick Repair: Harmonic balancer removal, air impact wrench, flywheel teeth

Question
I have a 1991 Olds Ciera with the 3.3L V6. The rubber coupling in the harmonic balancer has deteriorated, and I am attempting to replace it.  Trouble is I can't get the bolt out of the crank snout. I've tried an air impact wrench, and 3/4 breaker bar, but it won't budge. Is it possible that it is reverse (left-hand) threaded? Also, what's the best way to hold the engine still when trying to break the bolt loose?  I had a wrench on one of the flywheel bolts, and locked it against the frame, but I'm afraid of breaking that little bolt off.

Answer
Yes, Art, it is defanitely possible that it is left hand threads. I have no literature to look it up, but you sure need to make sure you are turning it the correct direction.
A wood wedge wedged between the flywheel teeth and bell housing sometimes works.
Van