Brake pedal is really stiff

I put new shoes and bled the brakes on this 67 Valiant before I got it on the road. After driving it for a while, I noticed the pedal is really stiff and only goes down a couple inches. When sitting at a light I was having to wedge my knee up under the column because the pedal was so hard to keep held down. It has manual brakes and the engine isn't idling too high or anything. I'm thinking maybe the master cylinder wasn't bled by the owner before me. What do you guys think? I can't think of what else it might be. Just want to get a little more info before I start tearing into stuff thats unnecessary.