"Master Power Brakes" issues with their kit

[coyote11]

Hello all, I have just purchased a '67 Firebird convertible. The PO had bought and installed a Master Power Brakes Kit, and I'm a bit perplexed by the issues I'm having. The brake pedal moves about 2-3 inches and then the brakes are on hard unless you feather it very gently. I've had mushy pedal before, this is just the opposite. I have Disc front Drum rear, the rears are adjusted very well. I have yet to stomp the brakes to see if the fronts are locking to soon. I have 15 lbs vaccuum to the booster, which in Colorado should be plenty to supply to the booster I would think. The pedal is very hard, anyone have any ideas what to check?