I notice a lot of the Chevrolet PU's I have been looking at are flex fuel.
That means there has to be extra "Stuff" on them and I am a big opponent of hanging on extras for limited reason.
I don't see me ever buying 85% low energy fuel.
Long story to ask . . .

extra issues/costs because it is "flex fuel"?

Ram or Chevy?
I am still up in the air
Haul moderate loads once in a while.
No heavy trailer dragging ever

The difference is largely in the fuel delivery system. Ethanol degrades certain types of elastomers and other components more than standard unleaded gas. Just because a vehicle is FFV rated it doesn't mean you have to run the stuff and it wouldn't dissuade me from buying said vehicle. By and large the differences are minimal.

^ I believe this is the case. A FFV is a regular engine with an ethanol resistant fuel delivery system. It's all good and no bad, as you have the option to use ethanol heavy fuel if you want/need while retaining the full HP and TQ while running on gasoline. What you may want to be leery of is the AFM (active fuel management) system that nets you an additional 1/2 mpg while destroying your engine.

Just about all half ton pickups are flex fuel these days. I just traded in my 2011 Ford F15o flex fuel for a 2017 version. No complaints. Regular gas has up to 10% ethanol anyway, so I doubt another 5% matters. You generally pay about 10% less for 85:15 than regular and get about 6-7%worse fuel mileage with it, there is a net savings.

E85 is 85% ethanol, not 85% gas, what you're talking about is 15% ethanol, that's not E85, that's E15.

I think the other posters who said the gaskets/seals are different are correct. I think there is a sensor that detects the ethanol/gas mixture content which the computer uses to change the fuel/air mixture.

I believe almost all V8 trucks now are E85 compatible. The V6 Turbo engines from Ford are not. My F150 with the 5.0 V8 is, but I'd only run that fuel in an emergency. And it'd be nice to be able to do so. I bet there were some stores that still had E85 long after they sold out of regular gas after Harvey.

I stand corrected and apologize for the misinformation. I did find though, that the fuel costs and fuel mileage differences were as stated. In the long run( at least with the Ford 5 liter V8) that is was about a 5 % savings using E85.

That's been around awhile at least with Fords. Ive never bought the Flex fuel. ever. No problems either. I rarely see it around here probably because it's not in demand.

A cheapskate hunting friend put E85 is a non-flex 6.2 Silverado. It ran a few hundred yards then totally puked out. They drained all the fuel, and lucky for him there was no long term damage. I had a 5.3 flex, and I never ran it because I was told the mileage was terrible. Locally there is a huge ethanol plant, so it is available, but nobody I know likes it.

Flex Fuel uses fuel line and engine components that are not affected by the increased ethanol . There might also be some mods to the computer to accomodate that as well.

My wife's car is advertised as get 28 MPG with E85 on the highway. I get 41 MPG on the highway with non-ethanol.

I am dropping an 04 Yukon L59 5.3 with a 4L60 in my 78 Cherokee, the only difference between the L59 and LM7 is a flex fuel sensor that monitors the ethanol in the fuel and report to the PCM to adjust the tune. I am looking forward to trying E85 in it once on the road.