Bi-functional lubricant additives exhibiting dispersant and V.I. improving properties are obtained by the Mannich Condensation of an oxidized long-chain high molecular weight amorphous copolymer of essentially ethylene and propylene having a number average molecular weight of at least about 10,000 and at least 140 pendant methyl groups per 1,000 chain carbon atoms, with a formaldehyde yielding reactant and a primary or secondary amine or polyamine, said reactants being employed in the molar ratio of from about 1:2:2 to about 1:20:20, respectively.