Why not test the line pressure with a $40 gauge first? If you find that the calipers dont put out enough, you'll have to do that anyway.



The equalizer gauges that go between the pad and disc can be found for less than $200 for a pair. They are used for checking dragging and/or unequal brakes.

A hydraulic piston's output can be found by multiplying line pressure by the area of the piston, minus any effectiveness lost in transit by an imperfect object such as a flexing caliper.

With power brakes and a 1.124" master, you should get about 600-800psi when really standing on the pedal. If you have a small scale, it should translate to about 100 lbs of foot pedal force.
This ought to put the 2.75" piston output at about 4000#s. With the squeeze of a caliper, this might double... not sure... makes my head hurt thinking about it. Let us know your #s.