This style has a baffle to keep oil in the engine, but no filtration medium, so it should be plumbed to the clea side of the air cleaner. Many aftermarket air cleaners have a nipple that can be installed for this. My personal choice is to not molest the new air cleaner base, and install a breather with filter in it, that will fit in the original location. Second option is to pack filter material into the breather can you have, and run it that way.