74 Duster, full build 6.4 conversion in Australia, rebuilding front end questions!!

Yikes!!! That had to have been banging around for years to do that. Can't imagine it was very stable on the road either with the LBJ moving around.

Assuming you can't source another one, I would carve out a piece of steel matching the thickness of the original and weld it in and grind it smooth to create the missing edge of that hole. You can't make it thicker there or the replacement parts (adjustable or not) probably won't fit right so I wouldn't plate over it.
Yep thats what i thought would of had a fair old clunk. And yes getting a new k frame not going to happen nd shipping would cost a fortune. I will scribe a piece of steel and weld it in. As its just locating the rubber and thankfully thick so will be easy to fabricate and weld. I will seam weld the whole k frame, and most likely strengthen the frame as well with the firm feel kit