Dennys' point is not esoteric nor is it just to work up the masses. "harmonic" issues with a long crankshaft are real. Why would a company that is driven by profit use a part they don't need? Why go from 4 main bearings to 6 when you made your "new" motor? The rubber insert is designed to damp the flexing at the end of the crankshaft. Like a shock absorber. The real question is are they "tuned"? Or do they just eat up the bigger deflections? I don't know. Maybe some one else does. Now look what you made me do with all them big words and long sentences. Hell, I can't even spell any more. Hotrod Lincoln has a very good point where he talks about internal versus external balanced motors. However, that has to do with dynamic balance and that is a function of piston weight, rod length, engine layout, and rpm. Not to mention rocking couples and a bunch of other stuff I don't know spit about. Now my head hurts and I hope you guys can stay friends.
