Kits, probably not.
Find your parts in a junk yard and make it work, probably your best bet.
I have the power box from a 78 GMC 6500, you may want to look at one of those in your search for the one you need.
I may use it on my 48 2 ton if I ever feel like my first setup is too weak for the truck after the engine swap to Diesel.

For pictures of my swap on an AD truck click below

•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-