http://www.jcwhitney.com/TUFF-COUNTR...8403_10614.jcw
Each spring is tapered, snub rolled and preset. Order the heavy-duty springs for tougher uses — will accommodate a winch and is much better for heavy towing. Teflon inserts, used on both types, help with ride characteristics and to reduce squeaking. Note: Sold individually but you must purchase 2 for both driver and passenger side installation.
I guess when I think of a lift kit I think leaf spring would beat blocks.