Heebsracin38

I have a 91 Honda Civic DX Hatchback that I race. Its been through quite a few races, and recently the brakes have acted up. They were good at idle, but when coming into the corner at wide open throttle, the pedal went right to the floor. So we got a brand new power booster and master cylinder, also in the past all pads and shoes were replaced, and the right front caliper as well. Well now, went out and raced it brakes felt good, but then they looked up, the pedal got stiff and wouldnt move. Any tips or suggestions??