Some simple hints with the AFB -
The carbs are sold by Edelbrock to be "about right" out of the box for a Cheb 350. In Mopar speak, this means too lean fora 340 or 360.
If your engine is modified - you really have to start from scratch, and asking what tune others run is probably the best way to get close.
Other tips:
Secondary jetting should always be less than the primary jetting. (This is the reverse of a spread bore carb design)
Start with the pump shooter arm on the richest setting (attach the pump rod to the hole nearest the piston) while tuning - this avoids off idle stumble issues being confused with jetting.
Choose the middle tension (pink?) Vac spring - generally this will work with most street cams - you can fine tune it later.
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Now this next tip is how I do it - its not the only way - but it'lll get you in the ball park much quicker.-
The idea is to isolate the primary side - like pretending you are tuning a 2BBL.
Here's how - Disconnect the secondary valve linkage (this is a small 'V' shaped link that joins tthe primary shaft to the secondary shaft. Its secured wth a couple of small circlips or similar.
This will make it so that only the primary butterflies operate.
(NOTE - You will need to secure the secondary valves closed as there will be nothing stopping them from being sucked open while testing and lean the carb out. A cable tie is usually good for this. )
Adjust your primary jetting and metering rods till you think you have the optimum tune for your primaries - and then reconnect your secondaries with the 'V' link and set your secondary jetting two stages leaner than the primaries.
From here, you will need to dyno the car or get an A/F mixture to achieve the best tune, but at least you'll be around the target.
