I purchased this items after researching to determine it was compatible with my 1991 Jag. XJ6. I received the part and attempted to install the very same day. The valve cover gasket was too small to fit on the boss grooves on the cylinder head. After several attempts and trying to use silicone gasket covers I gave up an reinstalled the old valve cover gasket using RTV. It old gasket sealed and I used the new spark plug grommets and seals and discharged the new valve cover gasket I had purchased. I WILL NEVER DO THAT AGAIN!!!!!!