I have a 454 I run 91


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I'm run 91 anything less it pings


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87 always and never a problem.

102

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WHAT!!!!! 😯


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Av gas


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I have a 455 I'm running 100 octane.


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VP-C12 

91 in havasu when its 110* out.  when its cooler ill drop to 87.  i dont have any crazy compression going on so theres no reason to run high octane fuel all the time.

Octane Rating All depends on how the compression of your motor will handle it (as its stated a few times on here)

That being said the higher the octane the better the fuel burn the better the mileage (Which in a boat you probly won't notice.

Run 87 if you have the compression to allow it if it pings run the next level up.  I don't know too many people running 87 with a big block anyway a small block I'm sure will have no issue unless its built and has big compression. 

Long story short run what your motor will allow your wallet to pay for

That being said the higher the octane the better the fuel burn the better the mileage (Which in a boat you probly won't notice.

its not really a "better fuel burn."  octane is a resistance to pre-ignition.  higher octane allows you to run higher compression, timing, etc.  if u have high compression and you run 87, the fuel will ignite before the piston reaches the top on the compression stroke.  you want to run the lowest rating you can get away with, without pre-ignition.  more octane than required actually burns LESS effectively.  factors like intake temps, etc will also influence pre-ignition.  keep in mind that what works at home on the trailer when its 70* might not work out at the lake/river when its 110* out.