Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by cryptobiotic, Jan 22, 2003.
What is the best fuel grade to use with a GM Crate 350 motor??
<font color="green"> If you're talking about the base model crate, it runs great on regular old 87 octane. Runs nice on the 89 also, but 91 burns too slow for the low compression. </font color>
Always start with the lowest rating the engine can take, if it detonates then go one step higher.
The higher you go in rating the slower the burn, less energy.
Start with the lowest. Break your engine in on that. I run the lowest octane in my crate and it is fine. I have also noticed that since I moved from Arizona to Colorado there lowest octane here is 85 instead of 87 which I ran in AZ. So far so good, but I have to bump up the timing a little still to.
well the idea behind octane is detonation. higher compression engines need higher octane but higher octane in your stocker means you can advance your timing a tad more to squeeze more power
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