SBC High Altitude Carb Jetting (1 Viewer)

Rockets2000

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Oct 11, 2010
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I live in Houston and am planning a trip to CO this summer to hit the Alpine Loop and surrounding trails. My '72 40 has a 350 with a 600 cfm 4 bbl Edelbrock (Weber) carb. Will I need to re-jet to lean out the mixture at altitude? If so, what size jets/metering rods should I go with? What do you CO guys run?

Thanks!
 
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Joined
Nov 12, 2010
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Unless it's already a tad on the rich side at sea level, I'd try it as-is. It'll make it. Otherwise, maybe 1-2 jet sizes leaner. Carbs are pretty good at compensating for altitude; most guys run what they have and accept it.
 

Cdaniel

Undocumented Mechanic-Not CDAN
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Run it
I've been from Phx to over 14k elev near Ouray and my Q-jet handled it.
You'll notice a difference in the way it runs though.
 
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I would leave it. It isn't going to hurt it running a little rich. If you lived there it would be a different story.
 

Rockets2000

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Thanks for the info guys. It is a tad on the rich side already, so I might go 2 sizes lean and see how she does.
 
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pb4ugo

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I've been out to CO a couple of times. You'll be good w/advancing the timing, when needed. Youll be able to tell when. I advanced timing until I got back to a good idle. On my Qjet, I also found limiting the movement of the power valve helped alot too, especially in then upper elevations.
 

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