Don't get me wrong, I like power brakes. Adding a booster will not and can not change braking if the booster is the only change. A booster will only change the amount of physical input needed to apply the brakes. I did this change on a '75 C-10. After I installed the booster, I went out to a favorite, nearly unused back road and and did a couple of "panic stop" tests. I had a sign post that I had used as a marker before the changeover. At 40mph I nailed the brakes at the sign. The old pick-up stopped at exactly the same spot as before, it was just easier for me to push the pedal. Now I know that this is about as unscientific as things get, but it worked for me.
Maybe one day I will add a booster to my '56. It will make it easier for my wife to drive, but I don't mind the old truck feel.
I don't recommend my tests to anyone else for obvious reasons.
have fun!
