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You've come to the right place for conflicting opinions.. I'll offer mine.. I've never needed any additives in my former L76 or my current L84. However, they won't hurt anything if you use them, except your wallet.
I am in California where even the premium is low octane. I rebuilt my 327 so that it had 10.1 to 1 and about 500 HP. After a while I developed significant knocking and run on after I turned off the key. I add 1/2 a bottle of Lucs Oil OctaneBooster at every fill up and now the car runs fine and no run on.
Good point, thanks. I had forgotten the two companies had merged.
Techron as a stand-alone additive can work well with modern cars with fuel injector issues. We have used it at the shop with a good deal of success, particularly on older GM engines (3.6L). For the car in question, it would be a waste of money.
I'm in the same situation as Scooter NYY and came to ask the same question which came up because I was reading the manual and saw that the minimum suggested octane rating for any corvette engine in 1965 was 99. I have a 300HP and the suggested octane is 99-101. I don't ever recall seeing an octane rating that high. Are fuels just better than they used to be not requiring the higher octane levels?
One other question. Do you all use 10% ethanol fuels in your car? I found a Chevron about 15 minutes drive from my house which sells ethanol free fuel for about $1 more per gallon. How big of deal is it to use ethanol free fuel in a mid-year corvette?
Last edited by rubixcube; Apr 14, 2025 at 04:45 PM.
I'm in the same situation as Scooter NYY and came to ask the same question which came up because I was reading the manual and saw that the minimum suggested octane rating for any corvette engine in 1965 was 99. I have a 300HP and the suggested octane is 99-101. I don't ever recall seeing an octane rating that high. Are fuels just better than they used to be not requiring the higher octane levels?
One other question. Do you all use 10% ethanol fuels in your car? I found a Chevron about 15 minutes drive from my house which sells ethanol free fuel for about $1 more per gallon. How big of deal is it to use ethanol free fuel in a mid-year corvette?
y
they measured gas different back then. if you drive your car regularly ethanol gas will be fine
Today's fuel is PON rated (an average of RON and MON ratings). Back in the day, fuel was shown as RON. You can Google "difference between RON and PON" and have a wealth of reading. Bottom line 93 Octane PON 10% ethanol will make your small block purr like a kitten. You can, probably, get by with the next octane down from 93. Just be sure to drive her as often as possible
And, that's the only gas I ever used in my '67.
fuel additives
Dennis
