The whole idea of the disc brakes with a booster is you have increased stopping power, is it not?
If disc are not going to be any better than good original drum brakes then stick with the drums and save the trouble and risk of a possibly cobbled together disc brake setup.

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-