351 octane

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04-23-2012 | 02:31 AM

2007 Green Machine

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From: Fort Atkinson, WI

351 octane

So, what level octane of fuel is everyone using with their 351?

04-23-2012 | 03:21 AM

jhoffy22

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I use 93. I don't know that it is necessary but it's what I have chosen to use.

04-23-2012 | 03:39 AM

RaceGass

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The compression ratio increased abit over stock I was told, and with the stock set up running hot enough to turn the header blue I have been running 91 octane. Hopefully it helps run abit cooler too.

04-23-2012 | 03:42 AM

jhoffy22

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Quote:

Originally Posted by RaceGass

The compression ratio increased abit over stock I was told, and with the stock set up running hot enough to turn the header blue I have been running 91 octane. Hopefully it helps run abit cooler too.

Stock compression ratio is 10:1. 351 compression ration is 12:1.

04-23-2012 | 04:48 AM

LikesToThump

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Quote:

Originally Posted by jhoffy22

Stock compression ratio is 10:1. 351 compression ration is 12:1.

My manual quotes 11:1....

04-23-2012 | 05:09 AM

wildcard

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i don't have a 351 (331 instead), i run 87. No detonation so far.

If it starts knocking on 87, go up to the next octane level.

04-23-2012 | 12:43 PM

Blackheart58

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Quote:

Originally Posted by wildcard

i don't have a 351 (331 instead), i run 87. No detonation so far.

If it starts knocking on 87, go up to the next octane level.

Exactly my setup and choice....and there are times I ride at temps exceeding 110 F!

04-23-2012 | 04:57 PM

2007 Green Machine

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Ok. Thanks everyone I guess I'll go with 87 and see what happens.

04-23-2012 | 05:11 PM

CousinLarry

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I've been using 91/93 since day one with my 351 and it runs good.. Never tried lower, maybe I'll try next tank as a Mr. Wizard science experiment..

I just figured higher compression would benefit from higher octane.