What about the calipers? Do they use right and left or two rights/lefts because of the non-staggered shocks. I ask because I see kits that say "two rights" for (fill in the blank) models. Those would be otherwise the same? F-body rotors can be had brand new easy enough.
The calipers are left and right, due to the e-brake cables pulling the levers on both sides to the front. I think the casting is the same but the worm screw for the piston is the difference to accommodate the different direction the lever needs to swing from left to right. I believe the E-brake cable brackets at the caliper and the levers are left and right as well. I found a few pics from my brother's build thread....
The real trick with this system is adjusting the calipers once they are mounted on the axle with the rotor and pads. You have to turn the piston to take up the slack between it, the pads and the rotor and then install the lever arm and let it rotate back to the stop. Otherwise, you have little to no emergency brake, no matter how much you tighten the adjuster and you basically have no back brakes. We have the Pontiac factory service manual but the write up on the procedure for adjusting these was difficult for me to understand. I ended up buying another reman caliper to work with on the bench. When you are turning that piston or worm screw (that the lever fastens to) it wants to pull down into the casting so you have to put the nut on the stud and turn the worm screw with a wrench on the boss that the lever mounts to. That way the wrench is sandwiched between the casting and the nut, the way the lever would be. This might not make sense. If you get to a point you are doing this, PM me and I'll talk you through it. We used all the parts for the Pontiac with the WS6 rear brakes including the booster, master cylinder and proportioning valve. Also, the pedal is different. The point where the push rod mounts to the pedal, in relation to the pivot point is different between the drum brake and rear disc cars.
My brother loves the feel of the rear disc system. I don't really care for it. I prefer rear drums. I like a high, firm pedal from drums that are adjusted pretty tight. The rear discs stop great. They just don't feel how I want them to. My brother's truck is rear disc so he's used to it. It's just a different animal.