You are going to create an ill fitting ugly mess. Tires sticking out, lost of modifications for cab and bed mounts, lift blocks, steering, bumpers won't fit, nothing will fit.
Options/Opinions
1. Buy a donor 2wd 60-62 frame and swap it to obtain a nice original undercarriage. Live with 2WD.
2. Buy a donor 4wd 60-66 chassis Chevy or GMC.
3. I would have to examine the cobble you speak of to decide if I could just fix it with EBay/Craigslist/junk yard donor pieces. Cut all the bad stuff off and put donor stuff on. The trans and motor mounts are the least difficult issue to fix.
4. Add newer 70's or 80's Chevy 4x4 axles, transmission and transfer case to the original frame. I have done that to a 1956 GMC suburban. I just sold a 1960 GMC 4x4 original.
It's ALWAYS much better to use an original frame. The 4x4's do not use torsion bar or coil suspension. No matter what you do, you are in for a lot of work and fab. You can't do it in an apartment parking space.
Consider no. 3 as your best option
