use a pcv valve to relieve crank case pressure or seals will start to leak. a spacer beneath the carb with a port is easiest or a nipple screwed into the intake
If that's all you have then that's what you use. Run the breather to the air cleaner. The pcv is just basically a controlled vacuum leak routed to the valve cover. That way if everything is working correctly, the breather works as an air cleaner for your crankcase, and all of the vaporized oil and other combustion byproducts go into the intake to be burned.