Try setting the gaskets in place with a very thin film of silicone on all surfaces. Before you install the adaptor, let the silicone "set" so it's tacky or skinned over, but not completely dry, this will help the sealing issue, and also make sure the gasket stays in place while you are assembling it. Do it on both sides of the gasket material and sealing surfaces. First to the adaptor to block interface, then the adaptor to oil filter housing interface. The silicone will seal since the gaskets supplied are crap. Trust me on saying they are crap.
You can also go to Napa or other parts store, and buy gasket material (make sure it seals in oil) and duplicate the supplied gaskets using a scissors and punch set. the gasket material will be a better beater add sheet (that's the technical term) and seal better than the "crap" that is supplied with the adaptor.
