Thank you to all for your inputs. I appreciate it.
Short, thanks for the comment on my other thread too.
When it comes to prepping a 60-66 truck for what I like to do, I've been down this road before. The 65 Carry-All in the photo below was bone stock when I bought in 1996 from the second owner. When a year later the V6 gave up I went through the whole truck. In went a 350, disc brake Dana 44 and a Dana 60 rear with 3.73 gears. The SM420 and T-221 were swapped for an SM465/205. It was a real nice driving rig. We did many a mile all over the west in that Jimmy, including a lot of dirt and rock.
I'm thinking of going the same route with this K20, except this time leaving the 420 & 221 in place and see how it works out.