Did you set the carb by using the vacuum gauge?

Also, connect the vacuum gauge so you can see it in the car and ride around. Make mental note(s) of what the readings are while motoring down the road. And pay special attention to the reading when it's idling weird....

I'm not a fan of the thumper cam but I can't say it's causing all your issues... But you need to identify what's changing when the idle goes wrong.. If the vacuum goes way up when the idle goes up then we can probably eliminate any air leakage.. If the vacuum falls off and the rpm's go up when it gets hot then maybe we do have an air leak being created.

Did you set timing by a light? what was the rpm when setting it? vacuum hose disconnected when timing?