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
That's because there is no relationship, Fred. I had bad luck with automatic transmissions, including 2 700R4s and a turbo 350. (Poor quality rebuilds, not because I had 4:10 gears.) I went back to a 4 speed manual and just swapped rear-ends.
What extensive welding do you think is required? The kit for my C10 with trailing arms was bolt on. I fail to see where full leaf springs would require welding as well. Like I said you have to torch off the shock towers on your donor but that's it. The u-joints can easily be easily be adapted (I went to a driveline shop and told them what different sizes I needed and they put it together in less than a day.) Brake lines required one brass adapter. I never hooked up the parking brake but could do so easily.
Long story short, it is much easier to swap rear ends than it is to change and adapt transmissions. I know. I've done both.
