Edlebrock carb off idle stumble - suggestions?

[70Sbird]

I've recently replaced the intake and carb on my 1970 440 and have an issue I'd like some real world direction on before I tear into the carb.
I had an Edelbrock performer RPM intake and a Holley 850 Double pumper on the car previously. The car ran well, and was great leaving a stoplight either in my neighborhood at low speeds or when moving off the line a little quicker This combo was really too tall for the stock hood and I wanted a more stock appearing engine compartment.
I swaped in a 1971 square bore iron 440 intake and an Edelbrock #1411 750 cfm vac secondary carb. I'm OK with the overall performance of this combo as this car is a driver and I'm willing to trade maximum performance for street manners.
The issue I have is an off idle stumble at light throttle; I need to give the car much more throttle to leave a stop smoothly than I did with the Holley. If I rev it up and slip the clutch more, it works great, but at light throttle it stumbles/bogs.
I've been reading on the internet and this seems to be a fairly common issue with this carb on larger displacement engines.
Has anyone had real experience with these, I just wanted a reality check before I go tearing into this carb and spend a bunch of money and time for marginal results!
Thanks!
Scott

[Ghoste]

They are set up on the lean side from the factory.  Is the accelerator pump hooked up to give the biggest shot?

[70Sbird]

Pump rod is in the hole closest to the pivot (most pump stroke) the "shooter" has .035 diameter holes, I'm thinking of moving up to the .043" version, and seeing what that does.

[68 RT]

By the edelbrock spring and jet kit from summit. I had to change the rods and springs. Made a big difference. My car was doing the same thing. May also want to change the primary and secondary jets.

[70Sbird]

what was your baseline, and how did you choose your changes? I have the Edelbrock manual and have looked at their Calibration reference chart. Where did you begin, and what ultimately worked, or was it trial and error?
Thanks

[68 RT]

I went up one step rich on jets, and moved up to the next heaviest spring. I did the springs first, still had a light stumble, then replaced the rods, this took out the stumble. Noticed after pulling the spark plugs I was running a little lean. Thats when I replaced the primary jets up one.

[lisiecki1]

Pump rod is in the hole closest to the pivot (most pump stroke) the "shooter" has .035 diameter holes, I'm thinking of moving up to the .043" version, and seeing what that does.

isn't the furthest hole from the pivot the most pump stroke?

[y3chargerrt]

Not according to the Edelbrock manual.

[lisiecki1]

Not according to the Edelbrock manual.

i just went and looked at mine and i understand why now....