FWIW my mom bought a brand new 1977 Aspen SE station wagon...came with the 2bbl "Super" slant six, and "deluxe" wire wheel covers.
On a side note, everytime she would go to work at Hudsons dept. store, some azzhole would steal her wire wheel covers! After about the third time, she had the dealer install just standard hub caps.
Also, a buddy of mine used to own a "77 Aspen R/T green on green, with the factory center console/bucket seats. His had a 318 4bbl. He did a little work, to the 318, and it was a peppy car, for what it was.

Don't I recall you saying it'd knock down 25 MPG on the highway? FWIW, that's the highway rating of my '16 300

In 1979 the Road Runner package required the 318 2bbl with the 360 4bbl optional.
In 1980 the Road Runner package came with both the slant and 318 (the 360 was no longer available)