Flex Fuel (51-83%)

my 11/1 , carburated 367, normally burns 87E10. I accidentally filled it up with something once, that I had to assume was E-85. I was on the side of the road three times in 15 minutes, upjetting the primaries. I had a dash-mounted, dial-back, timing box, so that took care of the different ignition requirements. It was on a roadtrip, so wasn't so bad, but I was more careful after that.