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Carb jets for across the pond

alextucker

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My tuning guy suggested when rebuilding my carb that I change the jets to suit the weather here. What size would you guys recommend?

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I think you have a 92 mains not sure of needles or secondaries. I can give you more info in a couple of days. If you need jets go to Quadrajetparts.com they have a large selection.

If you don't need originality. There are better carbs available.
 
I never did change any jets on a Carter ever. I did change metering rods and styles very often to see if it could do better. There are 2 step and 3 step metering rods which can really change how it performs. The metering rods are also changed from the top. Due to costs now-days it might be a good idea to measure what you have now using a micrometer and then search for a size smaller(same thing as bigger jets). You used to be able to buy Strip Kits that had a selection of jets, rods and springs. With the engine running at idle the vacuum holds down the spring loaded rods and at throttle(low vacuum) the rods would be up and the smaller rod size would give it more gas.
I have changed metering rods by the side of the highway and got 4 mpg better mileage. I also have had to stop and change the rods back with carrying any kinda trailer, was too lean. Small flat blade and 5 minutes.
 
Edelbrock tuning kits are too rich for that little AFB. You should open it up and see what jets and metering rods you have then buy a few sizes larger or smaller depending on which way you want to go. The metering rod spring kits from edelbrock will work. Again, you can get everything you need from Quadrajetparts.com.
It may be cheaper to buy a more modern cab with more CFM's
 
Alex Tucker,
From the 1967 Mopar shop manual re carb jets for a 383 engine.
Carter 4298S manual trans:
Primary main jet: 0.089" (carter # 120-389)
Secondary main jet: 0.068" (carter # 120-368)
Std primary metering rod: 0.064"-0.063"'-0.055" (Carter #16-404)
1 step lean metering rod: 0.066"-0.064"-0.058" (Carter # 16-171).
Carter carb # 4299S auto trans car
Primary main jet: same as std trans car
Secondary main jet: same as std trans car
Standard main metering rod: 0.062"-0.059"-0.051" (carter # 16-475).
All metering rods are three (3) step and can interchange. 3 step rods use a domed cover plate and are different from 2 step rods, which used a flat cover plate . The step up piston and spring are different lengths than 2 step piston and springs but are the same diameter. You can substitute 2 step pistons and rods for 3 step pistons and rods but you need to use the correct cover plate.
REMEMBER because the metering rod is fitting inside the jet, if you want or need to know the equilivant jet diameter, you must do an equivalent AREA calculation, subtract the areas and convert that number to a equilivant diameter. You CANNOT just subtract diameters because area varies as the square of the diameter (A=3.14 x r squred).
Search the internet for Carter carb parts....not just the Edlebrock Carter jet kits as they are only 2 step tods. Also scour the junk yards for old cars.... early GM was a great source for both 2 and 3 step metering rods pistons and springs....B4 they switched to predominantly Rochester carbs. I used to raid the junk yards....most of the time the junk yard owner's did not care what you removed.....and simply just gave me these small parts.....
Bob Renton
 
i don't think there is that much difference in weather between your weather and the middle of the u.s.a. i would be concerned with altitude more than humidity or temperature. i'd leave it alone, unless there was some kind of noticeable problem in the way the plugs are burning.
 
Lewtot,
I disagree....altitude is just one factor.....air density measured in pounds per cubic foot at standard conditions is the most important aspect which includes temperature, humidity and atmospheric pressure. These factors went into determining the carb's initial calibration.
If you suspect a rich or lean condition, read the spark plugs or use exhaust gas analyzer to determine mixture ratio....ideally 14:1.
But this is just my opinion.
Bob Renton
 
Lewtot,
I disagree....altitude is just one factor.....air density measured in pounds per cubic foot at standard conditions is the most important aspect which includes temperature, humidity and atmospheric pressure. These factors went into determining the carb's initial calibration.
If you suspect a rich or lean condition, read the spark plugs or use exhaust gas analyzer to determine mixture ratio....ideally 14:1.
But this is just my opinion.
Bob Renton
i said read the plugs. air density/humidity is a factor everywhere; including altitude. the old factory specs stated re-jet wasn't a problem with stock engines until altitude approached 5000ft.
 
I'm running a 2 step needle where a 3 step used to be and it works fine. I also used step up springs from an Edelbrock kit an they work was well. You have to experiment to see what works best for your conditions.
 
Alex Tucker,
From the 1967 Mopar shop manual re carb jets for a 383 engine.
Carter 4298S manual trans:
Primary main jet: 0.089" (carter # 120-389)
Secondary main jet: 0.068" (carter # 120-368)
Std primary metering rod: 0.064"-0.063"'-0.055" (Carter #16-404)
1 step lean metering rod: 0.066"-0.064"-0.058" (Carter # 16-171).
Carter carb # 4299S auto trans car
Primary main jet: same as std trans car
Secondary main jet: same as std trans car
Standard main metering rod: 0.062"-0.059"-0.051" (carter # 16-475).
All metering rods are three (3) step and can interchange. 3 step rods use a domed cover plate and are different from 2 step rods, which used a flat cover plate . The step up piston and spring are different lengths than 2 step piston and springs but are the same diameter. You can substitute 2 step pistons and rods for 3 step pistons and rods but you need to use the correct cover plate.
REMEMBER because the metering rod is fitting inside the jet, if you want or need to know the equilivant jet diameter, you must do an equivalent AREA calculation, subtract the areas and convert that number to a equilivant diameter. You CANNOT just subtract diameters because area varies as the square of the diameter (A=3.14 x r squred).
Search the internet for Carter carb parts....not just the Edlebrock Carter jet kits as they are only 2 step tods. Also scour the junk yards for old cars.... early GM was a great source for both 2 and 3 step metering rods pistons and springs....B4 they switched to predominantly Rochester carbs. I used to raid the junk yards....most of the time the junk yard owner's did not care what you removed.....and simply just gave me these small parts.....
Bob Renton
Great info the have Bob thank you
 
Really? You obviously haven't lived there. :lol:
united_kingdom_map.jpg
Even though they always leave us out of these drawings as if we have no weather I promise that lovely grey cloud formation continues on to Ireland too :) .... although lovely and sunny today :)
 
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