Unbolting 904 from 318 (anything to watch for?) Also question about rear axle (not 8 3/4)

I have the book (1973 Imperial Plymouth Chrysler) service manual. Maybe I didn't see it, but I couldn't find any mention or picture showing that tail weight.

https://www.forabodiesonly.com/mopar/threads/904-with-damper-weight-provision.219702/
Interesting.