Your trucks ECM is going to relearn and make adjustments on 85. Ethanol fuel may give you more power, but it has a lot of extra quirks you need to consider.

To start, ethanol fuels have about 33% less combustion power, which means you have to burn more fuel for the same amount of power.

This isn’t a big concern for race only vehicles, but daily drivers need to be aware of this lack of fuel efficiency, even with E85 being slightly cheaper at the pump.

Back when I worked at a GM dealership a local fuel company ran their entire fleet of vehicles on E85.  (not the diesel tankers, the smaller vehicle they had)  I made all kinds of repairs to them (famous GM transmission problems) but never made in repair related to E85 usage.   I've never owned a flex fuel vehicle.  

You guys are going to have to wait. Completely slipped my mind and I filled up wit 87

I noticed yesterday that E85 was only 30 cents cheaper than E10 at the station I was filling up at.  Gas is down below $4 a gallon around here.