360 Plug help

Looking at pictures for a speed demon 750 online. It looks to have screw in air bleeds that are not present in your picture. If you have them, put them back in as they were, you have to be pretty far down the tuning trail before you start playing with air bleeds. I would put the carb back to baseline settings, connect a vacuum gauge to it and start working on getting idle squared away with the vacuum gauge. On Holley based carbs, with it idling, you can slightly tap the accelerator pump lever. This will dribble a very small amount of fuel. If the idle picks up, you know the idle is slightly lean. There is a good tuning reference book you can get a FBO ignition. I think they used to blueprint demon carbs way back in the day.