I switched mine to disk on all 4 wheels and used a gm disk disk porporting valve from in-line tube, everything works perfect.
I would highly recommend the hydroboost setup over any vacuum booster I have tried. I have some pictures on my link. I bought the kit from http://www.hydroboost.com/. Very helpful and great service.

Grigg

•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-