Jianis,
If you are referring to fuel consumption, my guess is that you would not see much of a difference between a 216/235 in the same truck with same rear-ends at the same speeds. Maybe someone who has experience with well-tuned 216s and 235s in good conditions in the same truck will post their experiences?
I do not have any experience with a 216 and 235 in the same truck (or with the same rear-end gear ratio). I do know that my 1948 1/2 ton panel with a 216 (4.11 rear) got lower gas mileage than my 1954 with a 235 or a 261 (3.90 and then 3.55 rear ends). These are not fair or useful comparisons.
