DoubleV

If one took a CCC carb off a 305 and put it on a mild 350, would this cause the 350 to run lean due to jetting? If so, what can you do about it ( apart from ECM/chip swapping )? In a non CCC carb, you'd just re-jet and be on your way, but if you re-jet a CCC carb, the ECM will just compensate and give you 14.7:1 A/F ratio right? So how are you guys running big CID engines ( or beefy 305's ) on stock 305 carbs and ECM's?

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naf

Set dwell properly for the larger engine and you should be fine.

__________________
"A man who voluntarily drives a car like that and still manages to maintain such impervious confidence that it will faithfully start the next time he turns that key is an encouragement for us all to take greater risks in life."

DoubleV

I know you need to set the dwell, but there's got to be more to it than that otherwise all CCC carbs would be jetted the same no?

On my car, I had the dwell set perfectly, but it still wanted to run too lean. Carb is currently off right now due to other matters I'm attending to.

naf

How'd you verify that it was running too lean? Was the dwell pegging full rich under driving conditions? If so, there could be other causes.

Some members here have claimed that different primary jets were available for the ccc-qjet but no one has ever come back with sizes or any other quantifiable information.

I'm currently running a 350 with vortec heads and the comp xe 262 cam with the ccc-qjet from an '87 LG4. Driven it under varying conditions with the scanner attached and the stock jetted carb stays within adjustment range fine. I've used it under other, milder 350s with no problems.

DoubleV

I have zero problems with my dwell. It's where it should be and fluctuates to driving conditions as it should, but according to some of my spark plugs and a rough idel ( No vacuum leaks and carb is fresh ), some have told me it's running too lean. It ran fine on the old motor too.

Perhaps 14.7:1 A/F ratio is just too lean for idle on some cars?

BTW, I have ripped open an 83 ( I think ) CCC carb from an Olds 307, and it has 76 jets and 58U rods. My carb has a similar combo, but not sure exactly what just yet. I'll be tearing into it soon and find out.

What are the jet/rod sizes of any of the various 80's Chevy 350's with CCC carbs?

naf

Keep in mind that the ecm is only controlling the mixture for the primaries. The secondaries are still mechanical and metering is by rod and hanger size. You could very well be lean AFTER transition. If your dwell is staying in range during normal driving (mostly primary circuit) at least your ECM thinks you're OK.

Most sensor/component failures will cause a rich condition.