Well, since I got the car running right today, I am in the process of getting it insured and plated. I took it for a little bit of a "drive" down the street, and I notice that the brake pedal is soft. If I hold the brakes on, it will lower to the floor. They are power brakes, and the vacuum is hooked on the back of the intake. I dont think I used hose clamps on the line, would this cause a problem? There is no leaking fluid anywhere so far as I can see, and it is a new master cylinder. I had a shop install it back when the car was a 4cyl. (Still using 4cyl brakes). Any idea what could cause this?