Best fuel to be using in my 360

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DartVadar

DartVadar

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I've been thinking about this recently. My motor is a 360, and it has about 10.6:1 compression ratio with eddy closed chamber heads, and a mild comp XE268 cam in it. I have been running 94 octane fuel in it and I haven't experienced any detonation issues with it. The timing is set at about 16-17 initial and 35-36 total timing, seems to be happiest there so I kept it there.

The 94 octane fuel is readily available around me, but it has alcohol in it, which from what I understand isn't the best for the carb and everything, especially when I am storing it in my garage for the winter. All 94 it seems has alcohol in it around me, I usually go to petro-canada for it. I know at shell its either 91-92 octane and there is no alcohol in it. I'm not even sure if I need 94 octane, would I be better off with the shell fuel? Think I will experience some detonation issues with it?
 
Get the fuel with no alcohol in it. We only have 87, 89 or 91 octane here and it all has 10% alcohol in it. Your motor will do fine on the 91 or 92 octane and will store better. Worst case you'd have to adjust timing a couple of degrees but I doubt it will make much difference from the 94 your using currently.
 
What is the average altitude of where you're at?

At 10.6:1 with aluminum heads. 91 octane would be safe, heck I think you'll even be possibly safe with 89 octane.

My 360 has about 9.7:1 with cast iron '308' heads with a moderate 291THR7 cam in it. (I know, not the best cam, but I'm using it until I get either a Lunati or Howards).
I'm at 4500 feet above sea level, I can burn 91+ easily.
89 octane I can burn as well, it's not optimal but it works.
87 octane, no most of the time, it pings. There is one gas station nearby that sell 100% gas, I tried the 87 octane one and it didn't ping.
85 octane is a No Go for me.

Again I haven't fully tuned this car yet. I have set the timing at about 14-15 degrees.
But I am currently averaging 12-13 mpg (town+city+occasional heavy foot)
 
I use chevron 91 (10% ethanol) no choice in Cali....all gas has the ethanol here. For storage I regularly mix Marvel Mystery Oil in my gas to the specified mix. I've done it for years and never had an issue with gas separation or sludge buildup in any of my many vehicles I've had. Learned everything from an old school mechanic. If you run out you can substitute with Automatic tranny fluid. 4 oz to 10 gallons of gas. Upper cylinder lubricant which protects the valves and the whole top end. Keeps the carb from gumming up or corroding. Also adds a lubing quality to today's dry Eco fuels. Keeps the rubber seals and gaskets from drying out and cracking. Remember Lead was used to raise octane, lube the valve seats and lube the innards of the carburetor. Diesels always last longer as they have oil in the fuel which lubes the top end. One place that's lacking with gasoline. Engines always had the head issues and the top end over all. This method helps. I've seen heads pulled with people who used this method and it looked almost new, clean with minimal wear.I also add some to the engine just before an oil change to flush everything. Everyone has their own opinions and methods. I do what I was taught by my childhood neighbor and old school mechanic and racer. It works for me. I also have done this with lawnmowers and edgers and left them sit for months and they start right up. Saved a few as well that sat for a couple of years or more. Dumped out fuel, sprayed out tank with brake parts cleaner. Then sprayed out gunked up carb with brake parts cleaner. Added new fuel treated with MMO to the tank, sprayed out carb again with carb cleaner and starts right up. Let run a few minutes, adjust carb, and then good to go.

I just prefer to treat the gas with MMO or Auto tranny fluid in the proper amount. I have seen others use sea foam with success also but for me I buy the MMO gallon container rather cheaply and refill a bottle I keep in the trunk.


* Marvel Mystery Oil was developed back in 1923 or so to fight the build up of sludge in carbs on the armed forces airplanes. They used to get it in 55 gallon drums to treat the fuel. It's was first developed and designed for helping with fuel issues. As a carb that craps out or stalls out at 10,000 feet or more is a bad situation.
 
You can dump in a bottle of Star Tron fuel stabilizer right before you store it away. I do this for my hot rod, motorcycle, lawn mower & even the snow blower. Run it for a few to make sure it gets into the carbs & your good to go. It's amazing how much easier everything fires up in the spring. No more tearing the carb off the motorcycle every spring.
 
It makes the shelf life if gasoline drop significantly. My fiancée worked at a Sinclair over here in idaho and the owner told us the shelf life with 10 percent ethanol in any grade of fuel is 3 weeks max.
Plus ethanol is hard on rubber, such as fuel lines, power valves in carburetors, accelerator pumps in carburetors. If you can get ethanol free fuel get it, 91!to 94'octane isn't going to make that big of a difference.
 
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