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Jun 6, 2009 | 02:46 PM

hollenjoe

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Height

Im moving to a city thats 8630ft above sea level, which means my engine will have more trouble breathing, now questions, what do you think:

1. will a bigger carb help? more cfm?
2. will a bigger exaust help?

I know i have to calibrate my engine, just curious about those 2 things.
Im currently using a 750 edelbrock performer, i turn my 408 very rarely to 6k, but still do, I know a 750 carb is an overkill for a mild 408, so i thought it might do a better job on a high altitud...

opinions

thnx

Jun 6, 2009 | 10:05 PM

garypettengill

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From: USA

Don't get a bigger carb., there just isn't the air there to begin with. What you will have to do is re-jet your carb. When I lived in Utah at around 4600 ft. my 600 cfm Holley seemed to take care of business with a pair of 52 jets. When I moved to the DC area I had to jump up to 58 jets to get it to quit backfiring because it was soooo lean. Just watch your spark plugs and keep going smaller until you get the right color again. You also might loose a degree or two on you initial timing.

Jun 7, 2009 | 03:50 PM

hollenjoe

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I guess a bigger carb plus the poor air could hurt induccion and port velocity, i already have my 1407 rejeted, what about the exaust, shall i restrict it more or ..?

Jun 7, 2009 | 08:06 PM

ctubutis

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From: Denver Metro Area, CO

I've been at 5300' since 1978 and have never heard of anyone making any exhaust mods to
deal with the high altitude. As has already been posted, yeah, you'll need to rejet your carb,
approx one size for each 2,000 above sea level.

Where you movin' to? I'm in the Denver metro area.

-ct