After my last engine build having Cometic make me a custom head gasket they decided to make them available. When I did the last 2.3 I sent them a gasket and had one made. They had no intention on producing them but after my second order they decided to produce them for the public. Part # is C15317-000 They come in many thicknesses and you will have to specify that by the last 3 digits. So example for a 0.066" gasket. C15317-066 Here are the sizes they come in. Custom Gaskets - Cometic Gaskets. They are 89mm bore btw.