E85 has a lower boiling point than gasoline, so it is more vapor lock prone.
This is fine with the FlexFuel vehicles that have the fuel pump in the tank. Older cars with an engine mounted fuel pump need a fuel return line to prevent vapor lock with E85 and a 180 degree thermostat.
I don't think the combination of E85, an engine mounted pump with no return line, and a 205 thermostat will work.
