Which Gas

[60eldo]

    So here in canada we have 2 choices of gas. Shell 91 octane NO ETHINOL, or Peto Can 94 octain with 10% ethinol. Which do you prefer for your car.

[Dan LeBlanc]

My 390s all did fine on 91 ethanol free out here in NB even with timing advanced to 7.5 degrees BTDC from the factory 5 degrees. 

[Big Fins]

Unless you drive the car daily and it doesn't sit for any length of time, the 91 would be the way to go. Save the corn for feeding the livestock.

[35-709]

Absolutely run the non-ethanol.  The engines in both my '73 Caribou and the '71 472 in Big Red (as well as the 350 Chevy in the Jaguar) run MUCH better with the 89 octane non-ethanol I can get locally than on any octane ethanol-laced gas.  Especially nice is when the engine gets up to normal operating temperature, it will idle without the carburetor loading up, stalling, hard starting and increased tendency to vapor lock.  No-brainer to use non-ethanol, if you can get it, in my opinion, in our older carburetored cars.

[David Greenburg]

I agree, non-ethanol is the way to go if available.  If performance is an issue, try an octane booster.  A lot cheaper than carb rebuilds and other fuel system repairs, and probably cheaper than using an anti-ethanol treatment, which is what I have to do. 

[nycfarmboy]

go ethanol-free no matter the octane rating.  for a seldom driven car especially in winter months you don't want ethanol gelling back into corn syrup in your fuel systems.     Also ethanol will eat thru old fuel rubber hoses and can lead to engine fires.   

a 87 octane gasoline today is MUCH higher quality than what a premium gasoline would have been in 1973.... provided no ethanol of course.

[Big Fins]

I know I'm going to get flamed badly for this but, the tank on my Eldorado is 27 gallons. I drive it until there is about 10 gallons left in the tank, which doesn't take long. I will blend in an 80% blend of 90 octane Rec 90 gasoline and 20% 100LL AvGas. The engine runs so much smoother because of the higher octane and the 12^o base advance on the timing.

The 76, 500CID engine does not need the extra octane because of the low compression and the heads were designed for unleaded gasoline. If you did the lab tests on Recreational grade 90 octane, you will find it is base stock gasoline with no additives. IE: injector cleaners, carbon reducers, etc... And the AvGas has drying agents in it to make water suspended in the fuel come right out so that they won't find their way into the induction systems of aircraft. If you were to try and blend water into AvGas, it won't. It separates instantly.

Maybe once a year, I park the car in the driveway in such a way so that one particular corner of the tank is at the lowest level and run a small siphon hose to that corner. Only two times did I ever get anything out. That only equated to less than one ounce of discolored water.

Not everyone can get AvGas where they live, but here with all of the airboats, smaller airports will sell it to you at generally about $4-$5/gallon