sealing rear main oil seal on continental Z-145

I have main and crank bearing in place and the only thing keeping me from putting the oil pan on is sealing the back main bearing area on block. The rebuild kit comes with the string or light rope to push down into block on both sides. The shop manual says to use national oil seal cement or its equivalent. I do not know what either is but I am hoping someone here does. Can you advise please. Thanks

I'm going to guess it's something like Permatex gasket sealer, probably the kind that sets up. If I recall, that type of seal doesn't have any pressure on it, just need to saturate the rope with something to keep oil from seeping past it.