Adjusting 40+ year old bolts covered in dirt, rust and whatever that haven't moved in who knows how long? Could be a half a turn. Could be dozens. Who knows? It doesn't take much under the right circumstances. But really if the bolt stripped in the block that's an easy fix compared to some of the other things that could've caused that problem.
Really though you need to forget about a quick fix. Tear it down, inspect the suspension parts, and figure out what needs to be rebuilt and replaced. Maybe it just needs something easy. Or maybe the k-frame has to come out because the LCA pivot tube needs to be welded back into place. But looking at some of the things that have been done with that suspension you've got some shadetree crap going on there. It needs a close look at minimum, and realistically I'd wager a full suspension rebuild is in your future.
