So heres the one on CL I am looking at.
https://hudsonvalley.craigslist.org/pts/d/nice-1971-slant-six/6309394124.html

Heres another with a 904 tranny. But wouldn't this one be different as it is a 1979? I thought I read somwhere that the bottom end parts are different post 78?

The coronet in the junkyard I can have for $400 motor and auto tranny

At 56 years old with 2 bad knees manual trans is out of the question.