I have a 66 GTO that I just recently got out of the barn after a long winter slumber. I filled the tank with ethanol-free gas last fall, but am extremely nervous about adding the ethanol blended gas into it this spring. Anybody have any suggestions as to what one should do to prevent the ethanol from separating from the gas and what other problems I might encounter (clogged filters, fuel lines/gas tank worries, etc…). Any feedback would be greatly appreciated, Thanks
The 10% that’s in most mixes will not harm your car. You will, however, experience some reduction in mileage.
The ethanol concern in high concentrations when used in vehicles not designed for it is that it will attack polymers used in pumps, filters, fitings, sealing components and the like. At 10% it’s diluted well enough to be harmless to these items.
I’m pretty sure in a 66 GTO, fuel mileage isn’t much of a concern. 
I had a 65 Malibu that I ran the E10 blend in and didn’t have any problems with it
I agree that for drivin’ around gas E10 will be fine, but when it comes time to park it again, I’d run it down and try to fill it up with as much non-ethanol gas as possible.
Thanks guys, I will feel a little bit better about putting that crap in the tank. You’re right, my gas mileage will probably drop 10 miles a gallon to 9 but it’s worth it. The suggestion of running the tank dry in the fall woould be great except that ethanol-free gas is completely unavailable in this area. So for long term storage should I put it away with an empty tank, and risk condensation forming in the tank, or should I fill it with the 10% blend and add a fuel stabilizer. One guy suggested using a marine grade stabilizer?
I think a bottle of Stabil fuel stabilizer from the local auto parts store would work just fine. You might consider doubling the dose (in compliance with the instructions).