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Octane levels

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Old Mar 29, 2012 | 02:44 PM
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Default Octane levels
It has been forever since I have owned a carberated car so I am re-lerning tips and tricks for maintenance. Since the previous owner said the car sat alot, I filled the car with 93 octane to help flush the old gas. Is this helping or hurting the engine?

It is the original block that had a rebuild done about 15,000 miles ago.

Should I downgrade to 91 or start putting plain old regular in it?
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Old Mar 29, 2012 | 02:57 PM
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Assuming your engine still has the stock compression ratio, it was built to run on 87 octane gas. Higher octane than that is just wasting money with zero return.
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Old Mar 29, 2012 | 03:01 PM
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I always top of the tank with 93 after it sits for the winter because gas can loose it's octane level after a while. I'm not sure how long it takes, but I do it just in case. After that, I run 87 because my engine is stock.
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Old Mar 29, 2012 | 03:11 PM
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Thanks, I will have to track down the owner previous to the P.O. I bought it from. He didn't really know many details about any upgrades when the previous owner rebuilt it.

I just wanted to make sure I wasn't doing any damage.
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Old Mar 29, 2012 | 03:59 PM
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If your not getting detonation or it won't die when you try to kill it...
your ok.....should be able to run 87 unless its high compression.
We burn 87 in our 454 and it does just fine....
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Old Mar 29, 2012 | 06:49 PM
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excellent advise. I will be in this boat next month. Should he add Sea Foam as well to celan the carb?
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Old Mar 29, 2012 | 07:02 PM
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Originally Posted by ATIS
excellent advise. I will be in this boat next month. Should he add Sea Foam as well to celan the carb?
If you don't know when the carb was last rebuilt, you should just rebuild it. Cleaning will take care of any varnish in there.
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Old Mar 29, 2012 | 07:24 PM
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Originally Posted by ATIS
excellent advise. I will be in this boat next month. Should he add Sea Foam as well to celan the carb?
Unless his Corvette is powered by a WWII vintage 2 stroke outboard motor, Seafoam is of little use.
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Old Mar 29, 2012 | 07:38 PM
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I am concerned with mine have basically for all practical purposes sitting around for 37 years. I will take a look at her next month when I take possession of her.
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Old Mar 30, 2012 | 08:05 AM
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Thanks for the input, I will put 87 in when I gas up today.
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Old Mar 30, 2012 | 01:26 PM
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Originally Posted by 73Corvette
If your not getting detonation or it won't die when you try to kill it...
your ok.....should be able to run 87 unless its high compression.
We burn 87 in our 454 and it does just fine....

I do the same...........
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