1960-61 used breather tube: this tube connects to the block top cover housing and it goes through the cylinders, facing the ground. I have been using this type of vent tube in conversions when running single high performance air cleaners, and installing the small air cleaner on top of the shroud where the vent tube used to come out, to plug the hole for looks. All used parts might need to be cleaned. To see pix of the air cleaners installed in engine, please refer to: Easy tech tips" page.