When the cylinders are as short as they are in the 6.0L the pistons tend to rock in the cylinder at the bottom of the stroke and the bottom edge of the cylinder cuts the skirt. I have some wonderful pictures of the damage a 4" stroker does to a 408" engine. Yeah, I know a 4" stroke works on some engines but it doesnt work on all engines. A 4" stroke is great in an aluminum block GenIII but the cylinders are longer and the pistons stay stable at the bottom of the stroke.