Okay man, you do not have ot change the pedal rod! I ddi this in my '89 and there's a few things you can do...
Option 1, it's on MadXJ, getting the later style brake lamp switch. if you have cruise control you will have to ditch it in order to do this option, the newer brake lamp switch fits in place of the cruise control vacuum cut off switch.
Option 2, modify the new pedal rod. What you have to do to retain the Renix brake lamp switch is ream out the center hole in the pedal rod and then grind a flat on the leading edge of the rod, you will see when you get the two boosters side by side. I took this route as I watned to keep my (non functional!) cruise control. I can get some pictures of the mod for you if you need, got them on my home computer.
Sequoia