CPP does not have any disc brake kits for 3/4 or 1 ton trucks, not that I could find on their website, and not that I have heard of.

Several folks are inventing disc brake kits for these trucks, do a search and you will find many post.
these are some of the better ones: https://www.stovebolt.com/ubbthreads/ubbthreads.php?ubb=showflat&Board=1&Number=71226&Searchpage=1&Main=10902&Words=%2B3%2F4+%2Bton+%2BDisc+%2Bbrake&topic=0&Search=true#Post71226
another: https://www.stovebolt.com/ubbthreads/ubbthreads.php?ubb=showflat&Board=1&Number=65161&Searchpage=2&Main=10099&Words=%2B3%2F4+%2Bton+%2BDisc+%2Bbrake&topic=0&Search=true#Post65147
another: https://www.stovebolt.com/ubbthreads/ubbthreads.php?ubb=showflat&Board=1&Number=65442&Searchpage=2&Main=10144&Words=%2B3%2F4+%2Bton+%2BDisc+%2Bbrake&topic=0&Search=true#Post65434

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-