i think i am having issues with my car running rich.... any suggestions?

Ok, a few things are leading me to think my car is running rich. When i first start the car it runs great. after it warms up, it almost sounds like it has a slight miss but it doesnt sound like ignition. i replaced the plugs, wires, cap and rotor button anyway. when i accelerate, it lightly smokes a whitish smoke. it only runs kinda rough at idle. even though it smokes a little, it accelerates and maintains speed like a champ. im not losing coolant or oil so i dont think it is the head gasket. also while i am accelerating, i get a lot of valve-train noise... not sure if that is related to the same issue or not but if you hyave any suggestions, id definately appreciate it.

by the way, i dont think the car was used much when i got it so i did add a quart of Marvel's Mystery oil to the crankcase and some fuel system/carb cleaner additive to the gas as well after i noticed the smoking. i did find something on the internet about a mixture control solenoid on the carb... not sure what or where that is. can it be cleaned if it is varnished?