1986 k5 blazer steering slop
 

How do I change the steering box? I cant believe the original owner was driving this thing with 6 inches of slop in the steering for years!!!!!

unbolt it? You can adjust the bearing preload to take the slop out once it's off the frame.

Make sure your balljoints and tie rods are good.

a new AGR box is the path you want to take if you want a replacement box (check summitracing.com). Or, you can send your box off to redheadsteering. A parts chain "reman" box will be just like yours, only adjusted, cleaned up, maybe painted, and possibly with a new seal... When you turn yours in as a core it'll be for sale again without undergoing a full rebuild.

Jegs and summit both sell replacement rag joints, too (the rubber disc).

You'll also want to inspect the frame behind/around the steering box. A lot of them like to break out around the box.