Oil pan
I'd say the best way is to just replace the gasket. If you remove all of the old gasket (by annoyingly scraping all of the old stuff away), replace the gasket, and have all of the bolts back in and tightened to spec, it should work. Otherwise there is silicone RTVs (gasket maker) that can be used, but it always seemed like more of a temporary fix. I don't think it hold well for long term.
when you clean off the old gasket, get some brake cleaner and clean both surfaces very well. get some red RTV, high temp. and apply a thin bead to the cover and let it sit for an hour. then install it. thats what i do on mine and it never leaks. its even on the intake manifold and valve covers and diff covers on my s-10 with a 355 in it and they dont leak and motor has over 20,000 miles on it


