I didn't know such a condition could exist, but can it?

The new booster that was put in my 300 seems to allow the fronts to be REALLY "touchy" to brake pedal pressure, and there is a slight hiss heard from the under dash area (which was there before when the original power drum set up was still in place....not sure if it is booster or vacuum leak from the A/C switch).

Since it's been a decade *at least* since I've done brake work/had to use diagnosis on a brake system, does it seem reasonable that the "new" booster is faulty?

In the good news column, swapping out the rebuilt OE AFB to the reman 750 Edelbrock AFB has eliminated the stumble when the throttle is goosed !