The 1.125 will make the pedal very hard and will reduce the travel of the brake pedal.
1.125 is probably the largest bore you should consider. It generally speaking would be for a race car use to keep the brakes from locking up.
It's marginal for the street.
Here's a suggestion. A "Ford" profile master can be used in the Pantera with an adapter, or essentially a spacer.
Summit Racing carries these master cylinders in every bore size starting from 15/16", which is a stock 65-70 Mustang size, to 1-1/8", in 1/16
increments.
The reality is that the 1" is about what you are going to want.
If you like a harder pedal, the 1-1/16" will do that.
Any of them will have enough volume to work your brakes.
If you already have the 1" installed and you don't like it, try the 1-1/16"
The best solution is really to try them all going up 1/16 at a time until you find the one you like.
Most of the vintage racers seem to be using 1-1/8". A very hard pedal in a race car gives a feeling of security, but this is a street car.
I was using 1-1/4" with no power booster and stock calipers.
I went to larger calipers, reconnected the power assist and it was much too hard. I am at 1" now but am thinking of taking my own advice and trying a 1-1/16.
The 1" is ok but I want to reduce some of the pedal travel. The 1-1/16" will do that.
I won't know if it is the right combination until I try it.
