I have dual valve cover breathers to a catch can, total seal gapless rings on the forged pistons. The limited time I was on E85 with 8 PSI I didn't notice any signs of blowby on plugs/no oil in catch can or residue around breathers. All I noticed was puffs of white smoke from the breather which I thought was a blown head gasket (and prompted me to do a compression test) but went away completely when switching to pump gas. Not sure if that was normal with E85 or maybe the gas stations here just had crappy moisture ridden E85 in their tanks.