I am with mischif, I cut the old shaft to a stubby shaft length, weld up the oil hole in the end, Spin the bearings so they block the oil holes and plug the oil pump with a cap. I revved all my motors to the moon and the only time I had an issue is when i had the factory balance shaft in it, it siezed solid and snapped the B-shaft belt on my turck.

In the DSM world it is very rare to see a car with factory balance shafts still being used.