CRUZE 88

I installed the Scarebird front disc conversion at the time of rebuilding the entire front end. Somehow the brake booster was thrown out with the rest of the pieces. So I ordered a booster and master cylinder kit from somewhere. I had nothing but leak issues with the master cylinder and just replaced it with one from another project I have. The brakes work but not well and I get a rock solid pedal towards the end of travel. I have checked for vacuum leaks on the booster and it's holding pretty good. Any suggestions on an off the shelf master cylinder to use?
front disc and rear drum.