[Gene1949]

Originally Posted by FlatTopFreddie

Absolutely no doubt that ethanol fuel will burn in a cooler environment and/or a high pressure injection systems can handle, but conventional mechanical fuel pump systems will fail…

Check the boil temp of ethanol vs non-ethanol…. I have seen ethanol boil in glass/plastic fuel bowls, that causes vaporloc and engines do not run well on vapor.

I would challenge all that have never experienced a problem with E-10 to drive in an area where ambient driving temp is over 95 … you might have a new opinion….

Back in the day (pre-ethanol) we climbed Rose Mt highway on the way to Cartright ranch Lake Tahoe in August. Bone stock (6-volt, mechanical pump etc). Yes, it vapor locked and ran poorly barely making it.
Same trip across great Salt Lake into Salt Lake City. Same issue.
Point being, if you have a flathead and run a stock fuel system you are going to experience vapor lock under those sort of condition no matter what fuel you use. Clothes pins, tin foil, I’ve tried them all before I converted to electric fuel pump, electronic ignition and 12 volt..