4 wheel disc brakes

[Tom Goldman]

Your T-bird master cyl is 21mm or about 13/16".
It will work with 2 piston calipers, but would probably be undersized for a 4 piston front caliper. It also will work better with a low pedal , ratio like 4-1.
If you're using the stock pedal and it had power brakes ,thats about what most of them are.
Getting good brakes is all about balancing pressure with the correct volume ,while getting a comfortable feel for the pedal pressure required.