I fail to see the relationship between having a 4.10 rear end and "burning up 700R4's". Traditionally the main problem with 700R4's is not adjusting the throttle/kick down correctly.
Any replacement rear end assembly in that era truck will require extensive welding. If you have the skills and the equipment or can pay someone you are good to go. Other changes to consider are universal joints, brake lines, and parking brake components.
Fred
