Are they aware that the brake system needs to be kept in tip top shape and well adjusted now?
That's actually nothing new but the reduced stroke of the master cylinder is and now less room for error.
I'd be real hesitant to make such a modification to the brake system for someone else, and I'd still think real hard about the consequences if done on my own vehicle.

I understand this solved a problem and sounds like a real good thing, but it could also be bad.

•1951 GMC 250 in the Project Journals
•1948 Chevrolet 6400 - Detroit Diesel 4-53T - Roadranger 10 speed overdrive - 4 wheel disc brakes
•1952 Chevrolet 3800 pickup
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"First, get a clear notion of what you desire to accomplish, and then in all probability you will succeed in doing it..." -Henry Maudslay-