Based on all of your advice and having my car in our shop today, I think everyone's right about the problem. First we flushed the system A LOT with fresh DOT 4, then I went for a drive and noticed the same gradually stiffer brake pedal. After a few minutes of driving we pulled it on the lift and all of the wheels were difficult to turn by hand. The tech relieved pressure at a couple of the bleeder screws and the wheels were able to turn freely again. So obviously pressure keeps building toward the calipers but fluid is not returning to the resevoir. Therefore it's got to be a bad master cylinder, right? I hope that's all, however I also need a new right front caliper since one of the pistons is frozen in place. Oh well. I can't help but love the car no matter what happens. That's something probably no other car in the world could do for me. payne