i know there is alot of info and pics of the L body rear disk brake setup, but I think one think that is over looked or rarely mentioned is finding a way to use the mounting bracket that connects the hard line on the axle, to the caliper flex line.
so id just like to show you a very easy and clean, clever install to make this happen. I know of 2 different style brackets for this. I chose to use the straight one that i believe came from an 89-90 rear disk car. I ended up chopping most of the bracket off, and drilling and taping a hole into the bracket, and obviously drilling a clearance hole in the rear axle. I really should put the bolt in the other way and add a nylon nut to ensure that it does not go anywhere, but you get the idea