Convert from fotmal [lead] to slinch

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 (slinch)
The slinch is a unit of mass invented by the U.S. National Aeronautics and Space Administration (NASA). The unit is part of a system based on the pound of force and the inch. One slinch is the mass accelerated at one inch per second per second by a force of one pound; thus the slinch equals exactly 12 slugs or about 386.088 pounds (175.1268 kilograms). The word is a contraction of slug-inch. In the U.S. military aircraft industry, this unit is sometimes called a mug. It has also been called a snail.