No, you can't use the 1/2 ton kits.
Do a search on this site for disc brakes, this problem and it's solutions are discussed in several other threads.

Try this for how I converted my 52 1 ton http://www.stovebolt.com/gallery/mullen_grigg_1952.htm I will be glad to answer any questions you may have.

Or you could find spindles with disc brakes you like and adapt them to your original axle, I think someone in texas has done this with Dodge parts?

But as far as I know, nothing is just bolt on for the 1 ton disc conversion.
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-