The ring and pinion from Patrick's is for half-ton rears and won't work in your truck. I like the pumpkin swap from a late 60's early 70's 3/4-ton best for your situation, but they are not always easy to find. (Search this site for details on which ones fit.)
JiMerit is correct, that the '47 has the earlier bellhousing and transmission. To swap to a later trans you'll also need a later, through '53 bellhousing.
I don't recall when the 1-ton changed from huck to bendix brakes. You might look to update the brakes just a few years to have bendix type brakes. If you aren't pulling a trailer and keep the speed reasonable you would probably be okay.
Otherwise I've seen two approaches to putting disk brakes on a 1-ton truck. The hard way is to swap the complete IFS from a 3/4-ton or 1-ton Chevy pickup '72 - '87. The other hard way is to make your own caliper brackets and put rotors on your existing hubs.
If you update the brakes I'll want to know how you approach it and what you learn. I'm thinking about putting disks on a 1-ton and want to know all I can about how others have done it.
