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Man that thing looks solid!

X, Did you try here?

https://www.bjsoffroad.com/Small-Parts-for-Dana-44-and-Dana-53-Rear-Axles-with-Flanged-Axle-Shafts_p_54.html
...

gmwillys can help here I bet. I am thinking the "dirty ones" look like the Air Cleaner to Firewall brackets.

That is a great looking project. It looks like there is quite a bit of it there, and in good shape.