OFFY DUAL 1BBL Intake question

The problem of to rich at idle and an acceleration stumble may not be related. The stumble off idle is more often associated with a mis-adjusted/malfunctioning accelerator pump. Your holley's have an accelerator pump diaphram in the float bowl with an arm that sticks out and connects/rides on a plastic rocker piece. The opposite end of this plastic arm is directly linked to your throttle linkage. Check that when you move the throttle linkage that the accelerator pump arm I'm referring to moves (in I believe but it's been awhile) and initiates a fuel squirt.