When you use one of those 2\4 bolt adapters it must change your pedal height, no?
No for me.
Yes, you do want to insure the pedal winds up in the same place. For my two power brake cars, that is implicit because the pedal attaches to Mopar parts - one a Mopar booster, the other a Dart "stand-off bracket w/ lever".
For my manual brake car, I was concerned. Below is a photo showing the pedal will be in the same place in my 64 Valiant, when using the Breeze ABS MC and adapter plate. The 2nd photo shows the final assembly, stealing the bellows from the single-pot MC (super-glued), and an MC bracket from an Intrepid that is useful for securing parts (adj proportioning valve, etc).
Another thing to insure is that the A-body brake rod is secured in the MC piston. Were it to pop out, you might lose brakes. I used the factory rubber bushing on the end of the rod. In the first photo I had it on for a "test fit". When I decided to add the dust bellows, I tried to remove the rod and had to beat it out, tearing up the rubber bushing, so I would say it is secure. I used another bushing for the finale.
Finally, what to do with the "low reservoir" switch. First, steal the mating connector in the junkyard. It is 2 terminals that short when either float drops low. You can parallel it with an existing "brake warning" lamp that shorts to ground (e-brake?). Ex. my 1996 Voyager has 3 sensors that can short to ground to light the "brake" lamp - low reservoir, pressure imbalance, e-brake.
You might ask why I didn't post these photos before. I did make a post, but now it can't find it a few years later, searching from google, even using a copy of my words. Did FABO delete it? If so, I may stop providing free content.
