[leegreen]

I've relied on felpro

I see OS 5153 C fits 235 and 261 so it is probably not hard to get

My engineer father always used permatex red brush on gasket sealer with cork gaskets and I always did the same. If you do both sides the gasket becomes single use. I'd check for any pan bolt holes with deformed edges as dsraven described

I notice felpro has a video on gasket sealers, didn't watch it though