Put the crank in with two bearings and see how high the crank sets when resting on the high spots to determined aproximately how much needs to be removed.It's usually 4 or 6 areas near the baulkheads that need ground.The first step I would do is champher the interferred side of the journal if the crank isn't riding to high.Mark the areas that the crank rubs and carefully with a diegrinder dress those areas.Always put something in the cylinder incase you slip with the grinder.If it's way too much to cut then either cut the journal down or clearence the block.$300 to turn the counterweights and maybe get lucky,depending on how much material you remove,or $300/$400 worth of mallory weight to balance I think 3 or 4 hours with a pencil grinder and some care is cheaper. Even if you can cut the journals for free you may not get lucky and spend the money on balancing.Whatever you choose to do,good luck.