Mileage isn't the biggest reason for these questions, or I wouldn't own all trucks and SUVs...
I'm staying with the /6 for the "different" factor, I've had other vehicles I've removed the /6 for something bigger before, I've also had /6 vehicles I've driven with that motor for years too. Keeping that engine because "nobody else" seemed to over the years. Out of curiosity I want to see for myself "what makes a /6 tick" (besides solid lifters haha) I've done some of the "upgrades" typically done with a V8 to it, just because.
I'm more interested in (with everything else in the vehicle combo staying the same) other ways I can get some more "get up and go" besides swapping the engine for something bigger. And I'm sure I'm not the only one here interested in how much different drivetrain components (besides the engine) take to run, vs a different choice.

Heck, on one of the sites I frequent (FABO I believe) there was someone else asking about added power draw that adding power steering to something that was originally manual steering equipped.
I don't remember the outcome of that thread, and really don't care. (Someone out there apparently does though)
I'm not deleting PS. But I am adding AC. Something else I've seen talked about.
And no I'm not asking about what I am to "compensate" for that. Not at all. More just basic "mechanical curiosity" than anything else.