Just asks a parts house for a header gasket. It will be an off white color and feel kind of soft. The end bolt holes should be slotted so you can start the outside bolts with the header and slide the gasket down between the head and the header. After installing the gaskets and have driven it some, retorque the header bolts a few times until they won't tighten any more, then they will stay tight. Good luck,
Scott
