Nope, but I almost bought a used one a while back. My problem presently is a lack of disposable income. Well, a lack of income, period, or at least expenses being greater than income. Anything I do make that looks like money is getting spent on farm equipment parts, fuel, twine, and paying off a new tractor tire.

 

yea i here ya....i havent worked in over 2 weeks, so i got plenty of time to work on my truck, but unfortunatly it takes money wich i dont have.

 

I know OP is looking for a rear disc converstion for a heavy duty truck but I thought I'd share what I found for the 8.8
8.8 Ford Rear Disc Brake Kit

 

My understanding is that rear drums work just as well as rear discs. I have heard that mentioned before. Also, Some say that drums are actually better for towing. I don't know if any of this is true or not.