The guys at Suspension.com (209-578-5101) were able to help me out with a quick polyurethane alternantive for the rear bushings in the front Fabtech springs.

They sold me a set of BX428 bushings which are the correct size for the spring but the inner sleeve diameter is too small for the super duty leaf spring bolt.

I ordered a piece of 4130 Alloy Steel .75" outer diameter .065" wall thickness from McMaster-Carr to use as an inner sleeve. It comes in a 6' length so you will have to cut them to size.

I have been running them for over a year now with good results. They have already lasted longer than the rubber bushings that fabtech uses.