Make sure you did not delete the PCV valve connection on the front of the carburetor,which will have a hose running over the PCV in the valve cover. You want crankcase ventilation to remove moisture in the crankcase. The PCV is not an emissions device, its there to maintain the health of the engine. You can use a filtered breather cap in the other valve cover (that is where the air is sucked in), or keep the stock connection that runs up to the air cleaner housing.
B ruce