an inline 6-cylinder crankshaft is almost perfectly balanced to begin with due to the 120-degree separation of the rod journals. When we spun an inline 6-cyl. crankshaft up on the balance machine, it was the only one that could be run up to speed without bob weights. A V-8 crankshaft would try to jump off the supports if it was spun at more than a snail's pace without accurately-calculated bob weights attached. Ditto for V-6 or 4 cylinder cranks.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!