Tuning for altitude

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Raider L

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Shreveport, LA
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William
Truck Year
1974
Truck Model
C10
Engine Size
355
Weird experience years ago, I had never driven at any attitude above sea level, didn't know it had any affect on carb, timing, etc. Boy, I found out the hard way and almost got stuck in the mountains above Boulder, Colo.. I kept turning the idle jet up, down, this was a two bbl. on my slant six, until I finally got the engine running. I never thought anything about the air being to thin to ignite the fuel. I was still running the same settings when I left Louisiana. I still had to run a little lean because Denver is the "Mile High City".

@C10MixMaster,
What does that "13.4" mean as you are saying air/fuel mixture? I don't know anything about those things, my carb is totally mechanical. I don't ever have to be concerned about air/fuel mixes, but what are those numbers?
 

RawkerStatus

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California
First Name
Angel
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1986
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Suburban K20
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5.7
I'll be towing with the suburban, I'm thinking I might need to invest in efi to not deal with altitude change and fuel economy. On that note is the Holley Sniper kit better than the Edlebrock?
 

C10MixMaster

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Kingman AZ
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Ben
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1977
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C10 BIG10
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ZZ4 350
Weird experience years ago, I had never driven at any attitude above sea level, didn't know it had any affect on carb, timing, etc. Boy, I found out the hard way and almost got stuck in the mountains above Boulder, Colo.. I kept turning the idle jet up, down, this was a two bbl. on my slant six, until I finally got the engine running. I never thought anything about the air being to thin to ignite the fuel. I was still running the same settings when I left Louisiana. I still had to run a little lean because Denver is the "Mile High City".

@C10MixMaster,
What does that "13.4" mean as you are saying air/fuel mixture? I don't know anything about those things, my carb is totally mechanical. I don't ever have to be concerned about air/fuel mixes, but what are those numbers?


Yes that's 13.4 parts air to 1 part fuel.. Theoretical ideal is 14.7:1 , Richer to a point will produce more power and leaner to a point will get better mileage.
 

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