Fuel Octane... Whats Everybody Running?

[C10TN]

Got my 66 stepside a couple months ago and just now got it running and road-worthy. It's an in-line six and my question is... what gas should I be running in this old engine? I def will be using the local non-ethanol station but is the low 87 octane ok or would I be better off running 89 or 91? What's everybody running?

[markeb01]

Back when these trucks were new, any of the octane levels currently available would have been considered low octane regular. High octane pump gas needed to feed the factory 10:1 compression ratios would have been 100 or better. The only reason to spend more on a higher octane fuel today would be if it pings under hard acceleration on the cheapest regular grade (which is what I use). And it that happens, I’d try retarding the ignition a tad before wasting money on more expensive fuel.

[joedoh]

Originally Posted by markeb01

Back when these trucks were new, any of the octane levels currently available would have been considered low octane regular. High octane pump gas needed to feed the factory 10:1 compression ratios would have been 100 or better. The only reason to spend more on a higher octane fuel today would be if it pings under hard acceleration on the cheapest regular grade (which is what I use). And it that happens, I’d try retarding the ignition a tad before wasting money on more expensive fuel.

Yep yep yep.
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[KJSR]

I use 85 octane in my 1964/230 with no issues.

[corvettejim1968]

we dont even have 85 octane in Arizona i use 91 and it still pings when i get on it.

[KJSR]

Originally Posted by corvettejim1968

we dont even have 85 octane in Arizona i use 91 and it still pings when i get on it.

85 was not available in California either and when I moved to Utah I was surprised to see it. I use the 85 in all my cars (even my 36 with 10:1) with no issues. It's all how you tune and drive.....

[Torqueforce]

87 octane works fine for me, absolutely no difference between 87 and 93, running a 250 c.i. though with probably 8.5:1 compression.

[1963c-10]

Werent they also designed to run on leaded fuel?

[corvettejim1968]

yes the p.o. on my truck redid the heads in 1980 with hardened valve seats.

[rockdogg2020]

I use 87.
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[1963c-10]

I use 87 w/a lead gas additive. Dont have any issues w/knocking or pinging. Truck runs/idles happy.

[CRGRS 66]

I am running 94 octane from Shell as it is the only fuel sold in canada (ontario anyway) that has NO ethanol in it. It is an occasional driver so they extra dollars on gas is not that big of a deal.

[bbadfred]

Originally Posted by CRGRS 66

I am running 94 octane from Shell as it is the only fuel sold in canada (ontario anyway) that has NO ethanol in it. It is an occasional driver so they extra dollars on gas is not that big of a deal.

Isn't it also unleaded? I was told that leaded is not available in Canada?

[CRGRS 66]

Originally Posted by bbadfred

Isn't it also unleaded? I was told that leaded is not available in Canada?

yes, unleaded... can you still get leaded fuel in the US? Thought it was outlawed all together...

[GMR-PERFORMANCE]

11.2 comp with a rather large cam my dynamic is good for our 91 E 10 fuel.. Total 34 degrees timing.. All in by 2750.. 14 base with the MSD black bushing.

[jchav62]

I run 86 on all of mine. No issues. When I have a little extra cash, I'll fill it with super/premium, which around here is 91.

The 327 in the '62 is 10.5:1. No issues at all with either 86 or 91. No matter how I drive it. Base timing 10 degrees @ 7000' elevation.

[1963c-10]

Yes, the fuel is unleaded. The leaded is not for sale.....we have lead additives available through our parts suppliers though.