On the basis of some casual googling, the following are my best guesses
for some of the units mentioned in the Code of Hammurabi:
1 Gan ?=? 1 gin = .6 square meters
1 Gerah = 1/20 shekel = .4 g (silver?), according to the Old Testament.
1 Gur = aprox 300 liters
1 Mina= 1/2 kg = 60 shekels
1 Sar = 36 square meters = 1 garden plot = 60 gin
1 Shekel = aprox 8 g = 20 Gerah (at least in Israel)
1 Talent = 60 mina = 30 kg (not, I think, mentioned in the code but
shows up elsewhere)
Units I am still looking for are:
Ka (probably unit of volume) ??=?? cab, about 2 liters (Old Testament)
It looks, from various sources, as though the ratio of the price of
gold to the price of silver, by weight, was about twelve to one.