So is there a difference between a 318, 340, 383 and 440 flywheel. I know there is a difference between the 360 and 400. I know the 360 is weighted. I also assume there is a difference because of the crank's, one being forged (318, 340, 440) and one being cast (360). I know the early 60's- bb440's were completely different. Does anyone know the difference?