What you need to run E-85 is alcohol safe o-rings and seals in the fuel system including the pump and injectors. And of course you need a tune, the volume of fuel needed to reach a desirable air fuel ratio is roughly 60% more than straight gasoline and the standard tune can not adjust for that much more fuel.
My 07 F150 had a 5.4 and my 13 F150 had a 5.0 and both were flex fuel or E-85 capable and neither one had forged pistons.
Only run E-85 if you need it for the 105 octane rating, it gets terrible mileage. I tried it in my 07 and my mileage went from 13 mpg to 8