Here's an old farmer trick.  Use the Blue Wrench.

Heat the offending flywheel with a propane torch until it is very hot.  Too
hot to touch.  Apply ice cubes one at at time to the bolts for say three
cubes worth.    Then using a 6 point impact wrench socket and your breaker
bar, the long one that unca joel annoys the hornets with,  do the deed.

Repeat as necessary.

I have an inertia/impact hammer.  It fits an impact socket and you place it
on the fastener and whack it smartly with a hammer.

cheers,

pensioner