Mopar AVS help

I need a little help in getting my AVS to work right.
I am running a 70 340 in Pure Stock. I have a stumble / bog on the launch that I can't fugure out how to get rid of. I am not an expert on carbs, so any help would be appreciated.

I have tried different accelerator pump linkage positions, larger and smaller squirters, larger jets and adjusting to the air valve. None seem to completely cure the problem. The air valve seems to help best, if I put enough preload on the spring, but the stumble is still there.

Any suggestions would be appreciated.

Thanks
Mike Coates

IHRA 3914 D/PS swinger

Mike Coates