Will using Sea Foam affect octane levels in gas? [SOLVED]

Engine is a ZZ4 carb turn key crate engine with only 1,100 miles in a ’57 Chevy. Here’s my question: How does Sea Foam fuel additive affect the octane? Consider that I am using 91 octane. I need to use at least 92 according to the “GM Performance Engines” tech folks. I was considering using a pure octane booster. The only problem I have is a bit of run-on. To that end, I have tried everything possible to stop it. Even my pro engine builder friends agree it’s probably the octane rating of the fuel I have in the tank. I have read in many places I have read that Sta-Bil lowers octane ratings. Ergo my question. How does Sea Foam affect the gas? Thanks a million.

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Jim D.
Jim D.
3 years ago

Thanks for the question Dennis. Adding Sea Foam to fuel will not alter the octane. I also doubt Sta-Bil would change anything. Not a factor, anyway. To overcome the run-on (excessive chamber deposits), treat the fuel with Sea Foam and treat the upper engine through the carburetor throat with Sea Foam Spray. Repeat as frequently as you wish until the run-on problem is cleaned up. Hope this helps!