Agreed, the SSBC front disc set is a collection of mismatched parts not properly sized/tested, I'd toss the booster and master set up for factory Mopar related pieces, the calipers/rotors are usable
On further reflection this might be a better way to go. Just ditch the power brakes (master and booster) for manual. If I do that will I just have to replace the master cylinder? And if so, which one would you use? While retaining the SSBC kit calipers and rotors. I'd rather not have to put a vacuum pump on there.
I just went through the same thing on my '71 Challenger. The car was a manual drum 318 car, and I converted it to a 340 front disc car. The 340 was mostly stock, with a slightly hotter cam that would still allow daily driving. I swapped in ALL factory parts for the disc conversion. Still had super soft pedal. Vacuum maxed out at 16 at idle, but I never checked in park. I was about to trash the factory power setup, but with a lot of help from this forum I was able to diagnose the problem. It turns out that the pushrod from the booster had too much travel before making contact with the M/C. I never even thought to look at that as an issue because I bought the booster loaded and figured that would have been adjusted properly. After some adjustment, now I have power brakes! Check the pushrod distance and make sure there is not too much play.
