I have never been able to get this old beast to run right. She has a flat spot just off idle and acts like its running lean since the idle speed improves if I restrict air by placing my hand over the carb. I rebuilt it and raised the float level to no avail. Although, standing next to it at idle it smells rich. I replaced the accelerator pump which helped slightly but it still has a slight flat spot.
The carb is a Q-jet 7040511 which is mounted to an adaptor plate so, I assume this is not the stock carb.

Timing advanced seems to help but then it gets difficult to start when hot. I'm wondering if the advance mech in the dist might be stuck.

Any suggestions?