rear disc conversion
To get a drastic increase in baking you would have to step up to a multi piston caliper set-up. The old factory disc was a single piston that pushed from the back side of the rotor only. The multi piston Kelsey-Hayes calipers had inside and outside pistons for more even braking pressure on the rotors as well as more leverage for quicker stops.
Technically, a single piston caliper squeezes the brake pads as much as the opposing piston calipers because it pulls on the outside pad at the same time it pushes the inside pad.
What you gain from a fixed opposing piston caliper are:
1. Reducing resistance as the floating caliper body has to slide to apply pressure to the outside pad
2. Generally a much more rigid caliper body so more force goes into squeezing the pad and less into flexing the caliper
There are some other features such as less pad kick back and the ability to vary the piston sizes to better balance pressure (on 4+ piston calipers) but for the most part the advantages of a fixed caliper are due to a much more effective application of the pressure.
Note that this can be overcome with a floating caliper though. Years ago Ehrenberg did a test when he was swapping to Viper calipers on his Roadrunner (I think) where he did a couple of stops with the Viper caliper on one side and the stock floating caliper on the other. He said it still stopped straight, indicating that he didn't gain any braking advantage by going to Viper calipers. The stock caliper was big enough to overcome the disadvantages and resulted in zero gain. There are other reasons to do the swap, but in this case one of them wasn't more braking.
Note that I can't remember more specifics of the test so I don't remember if it also included going from 11.75" rotors to 13" with the Viper calipers.
Point being, don't assume that just because it has multiple opposing piston calipers, that it must be better.
