Just my 2 cents from working on the Generals front line since 1980, use a gasket or RTV but not both except for sealing gasket mating surfaces (i.e. oil pan side gaskets to rubber end seals).
BC 1960 Chevy C10 driver 261 T5 4.10 dana 44 power loc 1949 GMC 250 project in waiting 1960 C60 pasture art Retired GM dealer tech. 1980 - 2022