P51, nice work finding the KW Body Builders Manual!! The Weight Distribution appendix is good stuff!
My truck has an all steel, 3300lb., Interlift ILFS unit, and it is one tough piece of hardware. All pivot points except the deck hinges (I spray them with Dupont Teflon lube about once a month) are equipped with grease fittings and replaceable bushings. One nice feature is the Heck-For-Stout 3 piece ICC bumper. Click on the link below.
http://www.interlift.net/htm/pdf/ILFS.pdf
Rex