Originally Posted By: ZeeOSix
Notches in the leaf spring probably for strength and desired stiffness. Plenty of flow area for oil around the leaf spring without the notches.
That's right!
When Ford came out with their new tailgates on their 2009+ F150's, they had more lines in them. When I was reading the new truck specs, it stated Ford did that for more rigidity (stiffness). So, there you geaux.