I'm changing to E-85 in my 2001 Toyota Tundra right now. I add a gallon of E-85 to the first tank and increase it 1 gallon each time I fill. I run the tank until as close to empty as I can get. I'll stop at 50% and try that for a while before I try any further. People around here can only get to about 65% if the vehicles are not true "flex-fuel" vehicles. My dad is doing it with his 97 cad that needs premium.
I'll let you know how it goes in my 56. What the hell, at least it will be neat conversation
Regarding synthetic oil, manufacturers who produce E-85 recommend synthetic oil because they handle the corrosive and dirt by products of cumbustion better.

Tom
I.I. #1475