I understand how bob weight is calculated. I referenced my 6.1 Hemi crankshaft's bob weight only because I was asserting that it was stock and unchanged from factory. Thus, I am matching my rods/pistons/etc, overall, to the factory weights as to keep it all balanced together properly. My throwing out grams of this and that is only to show I have done the research and math regarding the parts I have verses the parts I am replacing. Keeping it all aligned as best I can...