Mallory metal is used when a LOT of weight needs to be added to a counterweight. It's actually heavier than lead. I static-balance my round track engine rods to 1/10 gram or less by using a triple-beam scale and one of those ball bearing rod hangers. Since a dollar bill weighs one gram, that's a pretty close weight-match. Ditto for weight matching piston/pin/ring assemblies. There's even a fudge factor on the dynamic (spin) balance procedure for figuring how much oil weight is retained by the spinning piston/rod assembly.
Jerry
Last edited by Hotrod Lincoln; 10/21/2009 10:30 PM.