1 The valves or lack of, have no bearing on the current problem
2 Your statement about "excessive travel" is OPPOSITE of what you should have if the master cyl. is "too big," causing harder pedal compared to old master.
SO.................
Did the brakes work "better" before you switched the master?
Did you do ANYTHING else, IE replace shoes, turn drums, replace wheel cylinders, etc, when changing the master?