340 vs 360 Difference in Harmonic Balancer Weights for Externally Balanced Motors

Ok were talking cast crank to cast crank weight balance difference from a 340 vs 360. I am asking because some harmonic balancers come with two weights and some only with one?

So is there a specification that someone can share for crank counterbalancing? I have a hard time believing that the same weight could be used here......