I bought this with the Edelbrock 4443 engine valve cover kit offered by Revain. Some reviews have said this breather doesn't fit these valve covers properly, but they fit perfectly with the ones I received. If you put a rubber gasket first, the vent will rise with no problem. Great product that looks great on my Chevy 350 engine. Great product Revane! Just keep such products and I will be your regular customer.