[Signman]

Believe Willwood has 2 bore sizes 1 1/16" 1 1/8"
The 1 1/16" will give a softer pedal more travel, opposite for the larger.
Where you want more braking power Front or Rear is where the larger volume section should be plumbed. On a drag car with slicks and narrow front tires the larger volume section should be plumped to the rear.