I just bought a new brake pedal. It should be coming today or tomorrow. I posted a question about 62-65 brake pedals and a member measured thiers and it was about 3" shorter, so I found a manual brake car and got that pedal. If we get it on the car this weekend I'll post the results.

If your car had power brakes, measure the brake pedal from the pivot to the bottom of the footrest, and the pivot to the brake pushrod attachment point. Divide that number into the first measurement and that is your pedal ratio. Find someone that has a true manual brake car and ask them to measure their pedal and compare. From the measurements that I got, on the early B-bodies the pedals are different.

The smaller master cylinder will help, but not solve the problem if the pedal ratio is incorrect. Been there, done that.