My father's 115 240 (74) averaged around 25 mpg. That was a little heavier body than the 123.

My 84 Euro 240 5 sp averages 29-30 at the moment, and I keep careful records.

True, my front end is a bit up in the air (Federalization - to bring the Euro bumpers up), and the valves need adjusting. The folks who get 33 out of a 4 speed must drive slower than I.