Quadrajet runs better without accelerator pump.

[NathansCorvette]

According to my notes, there are not big enough differences between 7044502 and for example 7044211 to cause the symptoms you are experiencing.

A too large inlet needle valve seat combined with too high fuel pressure will raise fuel level in bowl and start fuel delivery sooner than intended.

My 350 still has the original fuel pump, and all the fuel lines have been replaced with factory-style ones so I'm certain the pressure isn't high...

A new needle/seat was included in Cliff's kit and was installed when I rebuilt the carb. It did look different than the one that was in there. The picture shows this.

[NathansCorvette]

I'd start by looking at parts directly related to the problem.

Idle tube size?  DCR's, upper/lower IAB sizes, jet size, primary metering rod size, and the power piston hanger arms. 

Since the carb is not original and unknown origin it could be something as simple as the jets were drilled out, worn out, or too big for what you are doing.  Most carbs that come in here have bent power piston hanger arms leaving the primary rods WAY too high in the jets.

If the post is still present on the power piston check the power piston height.  Maybe someone bent the APT arm in the baseplate and the piston is too high.

Those carbs are known for being lean, especially the CA versions and on this new fuel there is no reason it's so rich right off idle that adding any fuel from the accl pump is causing a rich stumble......

I will take the carb back apart next week and measure everything and get back to you.

[Kenth]

My 350 still has the original fuel pump, and all the fuel lines have been replaced with factory-style ones so I'm certain the pressure isn't high..

You need to check to be certain, otherwise you´re guessing.
It has been reported that new "factory style" fuel pumps pumping out 10 psi or more, so you really need to test yours.

FWIW

[NathansCorvette]

You need to check to be certain, otherwise you´re guessing.
It has been reported that new "factory style" fuel pumps pumping out 10 psi or more, so you really need to test yours.

FWIW

Yes, you are right, I cannot say for certain that the fuel pressure is correct. I am confident though that the pump is the original unit due to the orange paint overspray on it from the factory.

I have a pressure gauge so I'll hook it up to the steel fuel line with a rubber hose when I have the carb off next to check out the jets/rods/etc.

[NathansCorvette]

All, I finally got around to taking the carb off and popping it open to take further look. I want to remind y'all that the issue (I think) I'm experiencing is a rich condition caused by something unknown to me. I determined this by unhooking my (perfectly working) accelerator pump and the over-rich bog I was fighting went away. Read more in my first post to catch back up.

Remember too that I do not know much about jet/rod sizing and specs. As mentioned in a previous post, this qjet is not original to the car, albeit the same year, and for a chevelle I found. It is not a reman carb, but was thoroughly cleaned and rebuilt by me a year ago.

My research found that the carb I have (7044502) from the factory had size 75 jets, 46B primary rods, and CH secondaries. These same specs are what the base L-48 corvette 350 qjet (7044207) came with too. Upon opening my carb, I found that it had these factory rods/jets.

My corvette has the factory hi-perf L-82 350, which should have a qjet (7044211) running 75 jets, 43B primary rods, and DA secondary rods.

Could the misalignment of jetting to the  engine type be the problem? If so, would simply changing to 43B and DA rods help?

Another theory I have regards the power piston spring. Could an incorrect spring rate for the vacuum  my L-82 pulls vs whatever a chevelle pulls cause the piston to rise too early causing a rich stumble?

Below are pictures of everything.

Note the last two pictures which show the primary rods/jets pressed/depressed. Is that large of a hole when pressed down right?

Thank you for y'alls help and expertise.