Convert from fotmal [lead] to packen [Russia]

Unit Definition (fotmal [lead])
The fotmal is a traditional English unit of weight for lead. In medieval England the fotmal was equal to 70 "mercantile" pounds, which is equivalent to 72 avoirdupois pounds.

Unit Definition (packen [Russia])
The packen is a traditional Russian unit of weight equal to 1200 funte, 30 pudi, 1083 pounds, or 491.4 kilograms.