Type of gas

[kodalee]

I have a 85 k10 with a chevy 350. What gas should I run if I can't find 100%. 87, 89, 91 with e10

[rich weyand]

With stock heads and pistons, 87 octane e10 should work with just about any setup, all the way to base timing of 16* BTDC.

[454Man]

I only run 89 or better... Better mileage and power.

What's under the hood??? If you have to ask maybe we shouldn't race!

[rich weyand]

here's the skinny on octane:
http://www.nicoclub.com/archives/gasoline-octane-myths.html

[454Man]

Dude that could very well be true if the engine is has efi,  but a carbed engine its obvious. you can clearly see the mpg and feel the diff in horsepower.

What's under the hood??? If you have to ask maybe we shouldn't race!

[Irish_Alley]

I agree with rich. The only reason I would switch from 87 to 93 is to eliminate knock. Main reason for knock is too high of a compression. Straight from Exxon
 http://www.exxon.com/usa-english/gfm/fuels_quality_gas_faq.aspx
I think its more of a placebo effect in most cases

[velojym]

It is. We had to be pretty conversant with the hows and whys of octane as airplane mechanics (lotta lead in that 100LL gas), and a carbureted engine won't show any increase in power or economy when fed higher octane fuel than it's designed to use in the first place. I'd go more into it, but the aforementioned articles do it far better than I ever could.

[greasemonkey54]

more octane allows use of more timing equaling sometimes, and only sometimes, more power. The ethanol hurts tho. In the summer I have to run 91 e10/15 to keep from pinging. winter I can run 89. If I find ethanol free I can run 87 year round, with pinging on only the hottest days, long trips, etc. and fuel mileage goes up

[rich weyand]

The ethanol hurts mileage.  Yet another reason to do away with the mandate.

[greasemonkey54]

it has less energy in it and takes more to create the same power. Fuel injection can automatically compensate for this