That cam is nowhere too big for your setup.You need to start at the beginning with the carb.The power valve has no effect at idle.Check the fuel pump pressure, float levels,power valve for a leak (this WILL affect idle),power valve gasket-not only for tears but position on the power valve.Before fine tuning be sure to set the timimg.I know I'll get flamed for this but a power valve in the 8.5 to 10.5 range will give excellent results with a properly tuned carb.
Ron