External engine balance - how's it done?

You take the reciproctaing weight which is piston, pin, rings, and small end of rod add them together. then you have reciprocating weight. then rotating weight is the big end of rod and bearings you get that number and times it by 2 because that is the number of rods per throw. Then you add in your oil weight which is about 3 to 5gm. then you have your bobweight. The formula is 100% rotating and 50% recip. That is for a v-8. Also I should at that most 60degree v-6s and 90degree v-6 with two rods per journal use the same formula.