It is a good idea to replace your valve cover gaskets during a valve adjustment to prevent leaks. These gaskets are crushable fiber-based gaskets that do the trick.
Note1: 2v gaskets are NO LONGER AVAILABLE. I do not have a source for these and do not anticipate ever restocking them. No, I don’t know where else you can get these or have a solution for you. Sorry.
Note2: DS1000 and DS1100 engines do NOT have valve cover gaskets. Instead they use reusable orings.
Note3: Testastretta (749/999/848/1098/1198), and DS1000/DS1100 do NOT use/need replacement valve cover gaskets.
Note4: Some 748, 996 and S4 models take different exhaust gaskets. Look at picture in the gallery of an ST4 type rocker pin plate. This plate is located on the left side of the vertical cylinder head. Near the top of the head between the cam covers is a rocker pin cover. This 5 bolt rocker pin style (1 bolt hidden beneath oil feel line) means the head is a ST4-style head. It was fitted to the 996, S4R, and to some 748 models. The exhaust valve covers on that model are different than the Non-ST valve cover